Teachers Reference - Annotations
Painting by Gustav Moore from Stone Wall Secrets.
Note: For convenience, each page and ilustration are named and begin with the red color. Annotations to the text are followed by annotations to the paintings.
To look for annotations by subject, link to Subject Index .
FRONTISPIECE (Boulders with Grass)
Scattered throughout New England  there are thousands  of stone walls  crisscrossing woods and fields  as if they have been there forever  . Each one has a story to tell, a story of farmers and oxen and hard, muddy work. And every stone in every wall also has a story to tell, an older story  of the land itself, of mountains and glaciers, of soils and seas.
1 STONE WALLS - Geography - Where are stone walls found? The geographic distribution of stone walls is quite uneven throughout the region. Walls exist wherever the soils of pastures and cultivated fields held a concentration of glacial stones. Areas that were never farmed, or areas where the stones were buried by mud from rivers, lakes, and the ocean have no stone walls, or have them only in unusual circumstances.
2 STONE WALLS - Abundance - How many are there in New England? There are tens of thousands, perhaps even hundreds of thousands of stone walls. Counting them is impossible, and the number keeps changing, as new walls are built, and as old ones disappear. But there are certainly a lot of them. Based on results from a questionnaire published by the U.S. Commissioner of Agriculture in 1871, there are 240,000 miles of stone walls in New England if the terrain east of the Hudson River is included. There are so many walls that it is difficult to avoid them.
3 STONE WALLS - Definition - What is a wall? What do they look like? A stone wall is any elongate row or stack of stones that was (or is) used to partition the landscape. Most of them are crudely stacked, reach just above the knee, and are held together without mortar. Some are little more than heaps of stone, whereas others are intricately laid, with the pieces carefully fit together.
4 STONE WALLS - Pattern - Do they really "criss-cross"? The word "crisscrossing" is not merely a figure of speech; it is literally accurate. Most stone walls bordered property or agricultural fields that were straight-sided, and which intersected each other in a criss-cross pattern, in some places like that of the game tic-tac-toe.
5 STONE WALLS- Abandoned- Why are they found in the woods? Walls that criss-cross the forest were once fields that have now become overgrown with forest, the so-called "secondary" forest of New England. Walls that still criss-cross agricultural fields are merely those that have been kept free of trees, most often because the land is still used for agriculture.
6 STONE WALLS - Antiquity - How old are they? Here we refer to the geologic story of the rocks in the walls, not the wall itself. The earliest walls that can be authenticated are those of the first English colonists and probably date from shortly after the arrival of the Pilgrims on the Mayflower in 1620. Undoubtedly, a few rare stone structures were built by Native Americans prior to colonization, but none are the conventional elongate stack of stones bordering an enclosure or serving as a foundation for a wooden structure.
"The old man stood on the porch of a shuttered white farmhouse . With his strong, tough hands  he gently unfolded the letter, and read it once again . The letter asked him to sell the stones , the ones from the farmstead walls. He folded the paper again. Distracted, he ran his fingertips along the creased edge. "Should I sell the walls, or not?" he asked himself . He could certainly use the extra money . Besides, the walls weren't being used for anything. So why did he feel so reluctant to sell the stones? Why did he feel so sad about letting them disappear from his land forever? He stepped off the porch onto the dew-covered grass. "I wonder what Adam will think?" His soft, intelligent eyes scanned the road expectantly, but there was no sign of his grandson. He strolled to the garden to wait, settling comfortably into the cushioned wooden swing the boy had helped paint last spring. It rocked him gently, body and mind--back and forth, back and forth--through space and through time. His thoughts drifted back to earlier days  when he and his sister were young. Oh, how they loved to play on the walls! In summer, they saddled stone ponies for a circus parade. In autumn, the wall was a pirate ship to sail on a sea of gold and red leaves. In winter, the stones became monsters with icicle teeth. And, in the spring, they jumped aboard their Stone Wall Express and chugged away to a far-off land."
7 HISTORY - Architecture - What is a farmhouse? The " shuttered white farmhouse" is the archetype New England house, one whose historical tradition dates back to the earliest Yankee settlers. White paint was the least expensive to manufacture, although cultural and religious reasons also accounted for its widespread use. Shutters, of course, were a functional element to early houses, serving to protect windows and provide additional security to the inhabitants inside.
8 SOCIETY - Elderly - How old is Grampa? We want to introduce the idea early that Grampa is a capable, intelligent, fully functional adult.
9 TEACHING - Reading - Why is the letter important? Here, at the very beginning of the book, we emphasize the importance of reading and writing by modeling both (reading a letter written by a stonemason). The book also ends with a reading of the same letter by a child, inviting a response from the reader.
10 ENVIRONMENT - Value - What is stone worth? This is an important issue in historic preservation that is quietly brewing on many fronts. The stone walls are clearly part of our common landscape, which would be much poorer for their absence. Yet more and more walls are being bought solely for their stone, then used to build finer stone walls for whoever can afford them. Prices vary, with slabby fieldstone commanding the highest price. In 1998 dollars, prices range from $200 to $600 per ton, which is a pile the size of a small pickup truck.
11 LITERATURE - Dilemma - Why is Grampa confused? Stories require a problem or a dilemma that must be solved. Here we point out the choice that must be made.
12 ENVIRONMENT - Choices - Does preservation cost money? Economics must play a part in every environmental choice. Grampa's dilemma is symbolic of the dilemma faced by every community when the choice comes down to environmental preservation vs. economic health. In this case, the economic pressure on families and communities trying to maintain rural property with limited outside income is very strong. More abstractly, cities, with their industrial wealth, often drain resources from rural areas.
13 HISTORY- 20th century - What has happened in Grampa's lifetime? Grampa, as pictured, is between 60 and 70 years old. Meaning that he would have lived on the farm as a child in the 1920's and 1930's. Although the agricultural economy of New England had been gradually weakening since the Civil War, many farms held on by keeping dairy cows. This industry nearly collapsed in the 1930's, owing in part, to advances in refrigeration technology as well as the Great Depression. This sent many of the remaining farms into ruin and forced farmers to rely on other sources of income.
BARN AND BICYCLE (Grampa reads the letter)
"A familiar voice interrupted his happy memories, abruptly pulling him back to the present. "Hey, Grampa!" shouted Adam, squealing his bicycle to a halt. The boy hopped off and shoved his bike against the barn. "What did you want?" he asked, gulping air in great breaths. "Your help," replied Grampa, who had walked out to greet him. "And something more important--your opinion." Grampa really did value his grandson's opinion. After all, the farm would someday be his . The boy, breathing more easily, quizzically raised one eyebrow. "My opinion? About what?" "Our walls, " answered Grampa mysteriously. "Our stone walls." He watched the expression on his grandson's face change from curiosity to bewilderment  . All Adam had been told was to come prepared for a long day of work. The old man hesitated. And then he told Adam their dilemma. A stone-mason was offering to buy the stones from the family's old walls. He wanted to take the stones from the walls, toss them into a truck, and haul them to the city where they could be built into grander walls around fancier houses. And he was willing to pay a fair price, just to take the stones. "I don't see any problem," said Adam, pointing to one of the walls, half-hidden in weeds. "Nobody here needs those old rocks anymore. Why not get rid of them and make some money , too?" "I wish it were that simple for me." Grampa sighed . "Come on. I've got something to show you. And we have some walls to inspect."
14 SOCIETY - Immigration - Why does Adam look different? Most of the stone walls were built by immigrants from northern Europe or their direct descendants. America is now a highly pluralistic, multi-ethnic society, families are changing accordingly, and immigration continues to play a strong role in American society. Grampa, as pictured on the facing page, is clearly Caucasian. Adam's racial heritage is more obscure, deliberately so. The important point here is that family values, in addition to real estate, are being being transferred across cultural and racial lines. This transfer incorporates the changes in contemporary American families.
15 STONE WALLS - Commonplace - What does Grampa know that Adam does not? Many New Englanders take stone walls for granted because they are an ordinary part of the familiar physical landscape. Adam's puzzlement reflects a common understanding that walls simply exist, and, therefore, are not deserving of opinion. Grampa knows otherwise.
16 ENVIRONMENT - Ownership - Can someone own the land? Adam doesn't see any problem in selling they walls because, for him, they have no value at all. This is one of the most critical points of the book; that the "land" -- in this case signified by the old stone walls -- has value that cannot be bought and sold. This viewpoint is central to certain Native American belief systems, and is also shared by the authors.
17 LITERATURE - Wisdom - If Grampa is so smart, then why is he confused? Children view the world in rather simple terms. At some point in their transition to adulthood, the world becomes more complicated. Wisdom involves the ability to make decisions when everything is taken into account.
CURIOUS ADAM (Adam finds the stone)
"The autumn weather was warm, the ground firm and dry. It was the perfect time to tour the old farm and patch any walls  needing repair--a chore that Grampa had always loved to do . Usually only a stone or two would slip to one side, jostled by frost or the roots of a tree. But once in a while, a short stretch of wall would collapse and need to be rebuilt. Grampa and Adam followed a well-worn path through ghosts of pastures now thick with pine . They hiked first through the small orchard, loading their pockets with fruit plucked from gnarled limbs . But along each wall, they slowed their pace, stopping now and then to return a fallen stone to its rightful place. After a while, Grampa paused to sink his still strong teeth into a juicy red apple. The golden September sun warmed him gently, soothing his spirit. The questions that troubled him, about selling the stones, faded away. Adam, lingering nearby, leaned down. From the moss-covered ground  he picked up a white, grainy stone . "Ahh--where do you think that stone came from?" quizzed Grampa. Adam faced his grandfather with a puzzled frown. "From the wall, Grampa, just like the others" he answered, not quite sure what the old man meant . Grampa grinned. He reached for the small, white stone, lifting it high into the sunlight , where it sparkled  in front of the boy's brown eyes. Then the old man began his story --a stone wall story -- one that took them back through time."
18 LITERATURE - Poetry - Why do walls need patching? This is a literary bridge to one of America's best loved poems "Mending Wall" by Robert Frost, who also took an inspection tour around his farm in New Hampshire each year. Also, the word "tumbled" is often attached to abandoned stone walls because, in the absence of repair, all will slowly come apart. This physical transition from "order to disorder" is an inescapable fact of nature, one commonly referred to as an increase in entropy.
19 LITERATURE - Interest - What child could enjoy that chore? Why kids like certain subjects and not others is often a mystery, even to themselves. Yet, it is in a child's fascination with some subjects and not others, that careers are often launched. Grampa may have loved this job as a child because he was drawn to rocks and landscape processes, an interest that may have sustained him through his professional training as a geologist.
20 ENVIRONMENT - Pine - There isn't much pine around anymore. Why? A dense stand of white pine, whose seedlings grow rapidly in sunny pastures unless cropped and trampled by cattle, was usually the pioneering forest on abandoned land, especially in southern New England. The pine, if not cut down for timber (which it often was), was later out-competed by shade-tolerant deciduous trees, usually beech, maple, and oak. Earliest in this succession, especially on sandy soils, is a pine forest.
21 ENVIRONMENT- Orchards - How can apples grow in the forest? Orchards, in order to be productive, must be carefully managed, which usually means irrigation and constant pruning. Untended apple trees survive well during the early forest succession, but their limbs are densely gnarled from the scars of ancient pruning. The fruit, of course, is often small, and blemished, yet still edible.
22 ENVIRONMENT - Moss - Where does moss grow? Moss-covered ground is very common in New England, especially near stone walls, because this primitive plant requires moist, acidic soils. Moss is a bryophyte, rather than a vascular plant; it requires a steady supply of moisture. Additionally, the light colored rocks of New England, generally lacking in alkaline elements, give rise to the acidic soils required for moss to survive. The moisture comes from the water-retaining capacity of our soils, which are rich in glacially pulverized silt fragments, and from the regional climate, which is moister than continental areas at the same latitude because the sea is closer.
23 TEACHING - Opportunity - Why is Adam curious about the rock? Grampa has been waiting for Adam to pick up something so that it would be AdamÕs actions that initiated the first learning opportunity.
24 TEACHING - Socratic Method - Why does Grampa ask the question? Teachers often teach best when they ask leading questions. This dialogue is our introduction to the Socratic method that Grampa will use throughout the book. Grampa's gentle probing is not only a teaching technique, but a philosophical inquiry into natural history, to the unwritten story behind what seems obvious. Indeed, the stone came from the wall, but the stone itself had to have come from somewhere. If the glacier brought it, then where did the glacier get it? And so forth. The dialogue here is about first causes, secondary causes, tertiary causes, etc., a logical ordering that was central to Aristotelian philosophy more than two millennia ago.
25 TEACHING - Demonstration - Why does Grampa hold the stone up? Here we illustrate a physical demonstration by Grampa, the teacher. Grampa knows that he has to hold the stone just right in order for it to sparkle. The sun has to glance off the crystals at just the right angle in order to see the individual grains.
26 EARTH SCIENCE- Crystals - What causes the sparkling? The sparkling results from reflections on the surfaces of different mineral grains. Most of them are probably quartz, the mineral that survives best on beaches because it the most resistant to decay and physical abrasion.
ARMORED MONSTERS (ancient fish)
"Look closely," said Grampa, offering the stone to the boy. "See whatÕs trapped in side." Adam turned the grainy stone in his hands like a kaleidoscope, squinting from the reflected sunlight. He glanced up at Grampa, then down at the stone, then back up again, not knowing what to say next. Finally, he saw what had been there all along, grains of clean sand, now frozen within the stone  . "Looks like sand to me," said the boy quietly, still unsure of himself . "Right!" confirmed Grampa. "It's beach sand. From an ancient ocean  that was here, right here , a very long time ago ." "Here?" protested Adam. "Here on this hill?" He tried to imagine foaming waves crashing there on that quiet, forested hillside. But he couldn't. "That's impossible!" "Is it?" replied Grampa. "The proof is in your hand." The old man licked his lips as if to taste the salty spray, then continued. "Those sand grains were part of a beach that lay at the edge of a vast sea, half a billion years ago. And in that sea swam primitive fish , like armored monsters on patrol. They swam past colorful corals that swayed like coconut trees . Mud and sand settled downward  --slowly, steadily, silently--in that ancient undersea world." Grampa looked up. A flock of honking geese flew through the clear, blue sky towards the other side of the valley. He blinked. The birds and sky vanished. The air was an ocean; the birds, a school of fish, swimming, swimming in a deep blue sea."
27 EARTH SCIENCE - Minerals - Do stones really freeze? Use of the word "frozen" in this context is figurative, meaning hard and crystalline. Most stones, however, are frozen solids because they crystallized from a melt (these are called igneous rocks). In this scene, we visualize this rock as a quartzite, which is most often made from quartz sand deep within the earth during metamorphism of sedimentary rock. This rock could be either sandstone or the even-harder quartzite, a rock too strong for the individual grains to rub off. Quartzite is a common rock in New England, but only rarely can the individual grains of sand from which it was made be seen.
28 TEACHING - Experience- Is Adam guessing? Or does he know? Learning takes place when something new is attached to something familiar. This is how Adam makes the "leap" to the idea that part of a beach can be held within a rock. We felt that this would give confidence to students trying to learn this difficult concept for the first time.
29 EARTH SCIENCE Iapetos Ocean Oceans last forever. Don't they? Most rocks that occur in mountainous regions, whether those from ancient eroded mountains like the Appalachians or whether from higher mountains in the process of being built by modern tectonic processes, originated as more mundane deposits from ancient oceans, oceans that are now gone, and whose disappearance comes later in the story. In New England, this ancient ocean was called the Iapetos Ocean. In Greek mythology, Iapetos was the father of Atlas, for whom the Atlantic Ocean was named. So, it makes sense that the older generation of ocean that was "here, right here" is called Iapetos. Even oceans are ephemeral by geologic standards.
30 EARTH SCIENCE Global Position Do continents really move? The "...here, right here..." refers to the location of the rocks on the continent, rather than on the globe. The quartzite was made near the place where the beach had been, geographically, but at a depth of about 10 miles. Since creation of the quartzite, however, the North American continent has been drifting westward on the globe, with the rock, and all of New England, moving with it. Meanwhile, the quartzite was rising upward through the crust as the mountains above them were eroded away.
31 EARTH SCIENCE Paleozoic How old is the earth? These rocks were probably made in the middle of Earth's Paleozoic Era, probably during the Ordovician and Silurian Periods, which ranges from about 400-300 million years ago. Paleozoic, which means "ancient life" refers only to the last half billion years of earth history. The earth is actually about 4.6 billion years old.
32 EARTH SCIENCE- Primitive - Haven't fish always been around? Fish were the first large, successful vertebrates, arriving on the scene nearly 400 million years ago. Most modern fish such as perch, bass, cod, sunfish, pike, etc. are quite recent inventions. Earlier, now extinct, orders of fish called placoderms, like the Dunkleosteus sp., pictured here, were heavily armored, and had primitive teeth and gills.
33 EARTH SCIENCE - Coral - Did stalked corals really exist? The corals with which we are most familiar are relatively recent inventions. Ancient corals, especially those that lived along the edge of the Iapetos sea, were usually solitary creatures. These so-called "horn corals" grew upward from the bottom on a single stalk, upon which the tentacles of the corals waved about capturing whatever plankton was drifting by.
34 EARTH SCIENCE - Gradualism - Do things happen fast or slow? Geologic events are not always dramatic. Most of the time, in most of the places, there is the quiet of erosion and the quiet of deposition. Abyssal mud, much of which is the remains of plankton, settles constantly on the floor of the ocean, waiting to be recycled into rocks.
"Eons passed ," he went on, now pointing at the opposite ridge. "The mud and sand were buried deep within the earth. There, miles below the surface, heat and pressure , bit by bit, baked the mud  into slabby, gray rock--rock that now fills all these walls ." Grampa waved his arm in a wide arc. Adam waited until Grampa turned away. Then he slipped the grainy, white stone into his pocket  , like a paperback book  to be read on a rainy day. Using both hands, he tipped up a heavy gray slab of stone. He noticed its many layers some milky white, others black with speckles . The young one said nothing while he traced them with his fingers and listened to the old one's tale. "Earthquakes rumbled, thrusting the mud into mountains . Volcanoes fumed. The smell of sulfur--like rotten eggs--spewed into the air ." Grampa inhaled deeply as if to sniff the ancient air. Adam dropped the heavy slab. It landed in the soil with a thud. "Wait a minute, Grampa," he said. "First you claimed the rock was ocean mud. Now you say it came from a mountain?" "It may sound confusing," said Grampa, "but it's true. The mass of layered rock formed first. Then, two continents rammed into each other, pushing the layers higher and higher until gigantic mountain ranges appeared . But mountains come and mountains go . Making them is the easy part; getting rid of them is much harder . Nature needs time, lots of time, for the sun, the wind, and the rain to break the rocks apart and send them to the sea ."
35 EARTH SCIENCE - Geologic time- What is an eon? We use the word "eon" in the familiar sense, meaning an almost unimaginably long period of time. In geology, this term has precise meaning; it is a group of Eras, each of which is a group of Periods, each of which contains one or more Epochs. Here, we speak of tens of millions to perhaps a hundred million years, which, for most people, is unimaginably long. Grampa knows better.
36 EARTH SCIENCE- Inside Earth - Why is the earth hot near its center? Most school kids know that the temperature within the earth gets hotter with increasing depth. This happens for many reasons, but primarily because the earth's interior is releasing radioactive heat which is being conducted towards the surface. The pressure also rises with increasing depth, in response to the increased weight of overlying rocks. What most students do not know is that the melting point of rock becomes higher as the pressure increases, meaning that rocks that would normally melt into glowing lava at the surface would not melt if buried deeply, where the pressure was high. As the muddy sediments of Iapetos were buried the first thing that happened is that the sedimentary particles were pressed together tightly, and excess water was squeezed out. Cementation was the next thing that happened, in which the grains were cemented against each other with silica and calcium. But most of the rocks of Iapetos were "buried" even more deeply, so deep, in fact, that the sedimentary rock was transformed into metamorphic rock, a term we use to mean that the form of the rock was fundamentally changed by such extreme conditions.
37 EARTH SCIENCE - Metamorphism - What happens when rock is baked? "Baked" is an imprecise term because it connotes temperature only. Just as important was the incredibly high pressure which allowed the rocks to stay solid even at a depth of many miles. Although these materials didnÕt melt, they were completely recrystallized, and plastically deformed -- stretching, bending, squeezing -- into contorted layers.
38 EARTH SCIENCE - Lithology - Why are New England's rocks slabby? Most of New England's rocks are high-grade metamorphic rocks, meaning that they have been changed drastically from their original form. Most are foliated, which means that they were layered by the metamorphic processes. One very common foliated metamorphic rock is something called a gneiss, which has bands of different composition that are distinctly visible. When layering, like that of wood grain, is visible without compositional banding, the rock is called a schist, which is usually rich in mica. Whether gneisses or schists, it is the layering that accounts for the slabbiness of most stones in New England, and, thus, for their abundance in stone walls. The same is true in other countries where stone walls are common, notably the British Isles.
39 TEACHING - Collections - Why do kids collect things? Kids have an instinct to collect things, especially rocks. Adam collects the rock secretly, not wanting Grampa to know that he is actually becoming interested.
40 LITERATURE - Foreshadow - How is a stone like a book? The idea that a stone is a book foreshadows the future, when Adam will view the walls as libraries of stone books. This action represents the perfectly normal response of taking a field sample, one that will be investigated more thoroughly later.
41 EARTH SCIENCE- Mineralogy - What are layers made of? As mentioned earlier, the layered rock so common in New England stone is called a gneiss. The milky white layers are dominated by feldspars and quartz, two of the most common rock-forming minerals in the earth's crust. Quartz is made of nothing more than silicon and oxygen. Feldspars also contain aluminum and one or more of the alkaline elements like calcium, sodium, or potassium. The black layers with speckles are the dark, generally black, iron-bearing minerals. Biotite is a black mica; hornblende is a kind of crystal called an amphibole; augite is a common pyroxene. Small black specks can be the magnetic bearing mineral called magnetite. Garnets, often rusty in red in color, are also common, especially in schists.
42 EARTH SCIENCE - Tectonics - How can mud be thrust into mountains? Earthquakes are a perfectly normal part of the mountain-building process, and are especially common in places where the earth's crust is being pushed, or thrust, together, such as along the margin of the Pacific Ocean today. This sentence describes the process of subduction, in which the ocean mud, now turned into soft sedimentary rock, is caught between the descending oceanic plate and the edge of the continent. The mud is stacked into layers, each of which is bounded by something called a thrust fault, against which materials are slivered and stacked together.
43 EARTH SCIENCE - Volcanoes - What comes out of a volcano? Volcanoes do much more than produce liquid lava. They also produce solids and different types of gas. The solid phase consists chiefly of pre-existing parts of the mountain that are blasted into the air during explosive eruptions. The gas content of volcanoes is also very important. The smell of rotten eggs, the signature volcanic gas, is hydrogen sulfide (H2S). Importantly, nearly all of the earth's atmosphere, is thought to have been produced by the exhalation of volcanoes, which have been smoking away since the earth began. In fact, the ocean, all of it, is a liquid that condensed from water vapor released by earth's volcanoes when the earth cooled below a critical temperature.
44 EARTH SCIENCE - Mountains - Can continents actually collide? Yes they can! Continents move as relatively light masses of crustal rock that are embedded within rigid plates making up the outer part of the earth. When two continents collide, they are so light in mass (relative to the heavier, darker, more plastic rocks at depth) that neither can descend into the earth. Thus, they slowly collide, crunching together into a giant collision that can be hundreds of miles across and take millions of years to complete. Gigantic mountain ranges are the result.
45 EARTH SCIENCE - Rock cycle - Can mountains really disappear? Mountains can form, be eroded to stubble, then reform in these collision zones many times. The process is, at least theoretically, both endless and timeless because high mountains invite rapid erosion, and the ocean basins that receive the sediment from eroded continents are destined to be turned back into mountains, when the ocean closes. Over eons of time, this is called the rock cycle. Like the hydrologic cycle, matter is constantly recycled through the earth. But the rock cycle takes time, lots of time.
46 EARTH SCIENCE - Denudation - How long does a mountain last? Typically, a mountain range can be created in as little as several million years. In contrast, it takes tens of millions of years, in some cases even a hundred million years, to reduce the mountains to lowland plateaus, which is what much of New England is.
47 EARTH SCIENCE - Weathering - Why do rocks decompose? This phrase is merely a poetic description of what is called weathering. Rocks disintegrate along pre-existing weaknesses, often along fractures which opened up when the load of overlying rocks is removed by erosion. Then rainwater combines with carbon dioxide from the earthÕs atmosphere to produce a mild acid that begins dissolving the rocks, a process that is greatly speeded up by the decomposition of organic material in soils. Rock fragments, when small enough, move downhill within the soil in a slow creeping process called, not surprisingly, soil creep. Once they enter a small valley, they are swept towards the sea, intermittently, by running water.
FROZEN GRAVEL (Grampa imagines the ancient stream)
"I'll show you what I mean," said the old man. Without another word, Grampa squatted down to study the nearby wall. He lifted stone after stone, pausing now and then to flip one over. "I've got one!" "Got what?" asked Adam. "Here, have a look for yourself." Grampa stepped back . Adam noticed the pebbles right away. The way they stuck out of the brown, muddy sand reminded him of peanut brittle--except that these "nuts" were different sizes and colors. "It's gravel, isn't it? But it's as hard as cement !" "You're right," said Grampa. "But this gravel has been cemented by time, deep within the earth. The pebbles began their journey in a mountain stream . They bounced along the river beds towards a distant sea, growing rounder and smoother with every mile . All these pebbles eventually washed together to form an ancient gravel, which we can see in this rock today." Grampa stood silent and still in the shade of the trees. The breeze, blowing through the October trees, seemed like the rush of a distant river, echoing up from the valley below. The fluttering sound of leaves became the muffled sound of pebbles, bumping each other beneath the flowing water. Adam, too, said nothing . A few moments passed before they resumed their hike along the trail. The path sloped gently, higher and higher, until it reached an overlook  where they could gaze upon the farm and fields below. It had always been Grampa's favorite spot. There, at the edge of his land , tucked into the corner of a wall, he had stored a special stone ."
48 TEACHING - Withholding - Why didn't Grampa answer him? Again, Grampa does not answer AdamÕs question. Instead, he forces the boy to make observations. Of course, these situations always end with Adam being correct, because Grampa would not lead him astray. He just wants to make him work a little.
49 EARTH SCIENCE - Conglomerate- How can gravel be hard as a rock? This rock is called a conglomerate. By definition, it consists of rounded pebbles within a matrix of sand (or mud). The different colors result from the fact that its pebbles came from a variety of rock sources, all of which were slowly integrated as the gravel moved down river. Like the quartzite already encountered, the gravel was cemented firmly during an interval of protracted deep burial when chemicals in the groundwater precipitated between the pebbles, cementing the rock firmly together. Conglomerates are found widely throughout New England.
50 EARTH SCIENCE - Streams - Where do pebbles come from? Water, sand, or any material can only flow from an area of high potential energy to one of low potential energy. Mountains have the highest potential energy, and therefore fall apart the fastest, meaning that the rock fragments from which most pebbles are produced began in the highest valleys, or the slopes above them.
51 EARTH SCIENCE - Rounding - Why do pebbles become rounded? In the simplest sense, pebbles form because the corners of rock fragments get knocked off; the same thing happens in the tumbling mill of the lapidary shop (rock shop). This rounding is a consequence of the fact that a sphere is the geometric shape with the lowest surface area, relative to its volume. Most pebbles can never reach the ideal spherical shape because the rock fragments they are made from are not uniform in shape.
52 TEACHING - Waiting - Does Grampa "space out?" It takes time to process information. Periodically, Grampa takes the time to let the lessons seep into Adam, rather than rushing off into another subject.
53 EARTH SCIENCE - Cuesta - Why don't hills have the same slope on both sides? Asymmetric topography, in which gentle uphill slopes end in ledges, is characteristic of New England hills. This is because most of New EnglandÕs rocks come in layers that are tipped. The gentle side of the tipped rocks is called the dip slope. The steep slope is called the scarp slope. At the scale of a town, the pattern of ridges and valleys is often defined by these belts of strong and weak rocks, respectively. This landform is called a cuesta.
54 LITERATURE - Setting - How far have they gone? Here we mention the edge of the land to let the reader know that the pair will not wander aimlessly. Knowing that we have already reached an edge lets the reader know that we have already gone somewhere.
55 LITERATURE - Archive - How long can stone last? Here we plant the idea that special stones can be placed and stored, like books on a bookshelf. Later we are more explicit about this. For now, we merely allude to this important idea.
FEEL THESE SCRATCHES (Grampa and the glacial stone)
"Reaching below the silken cobwebs, Grampa pulled out a smooth, black stone covered with tiny scratches. "This stone tells one of my favorite stories--the story of the great Ice Age ." Twenty thousand years ago , a giant glacier oozed southward over all New England, smothering even the tallest mountains with ice . On top, the glacier was a snowflake desert ; frigid, white, and blinding beneath a brilliant sun. On the bottom, the ice lay in total darkness ; it pressed the brittle, broken rock back into hard mud ." Grampa suddenly felt very cold . "Feel these scratches ," urged Grampa as he blew away dust  from the stone. Adam rubbed his fingers over the shallow grooves on the dark polished surface. "Can you imagine the grip of that glacier, the grating and grinding  of stone against ledge?" Adam shivered. He knew the sound of two stones scraping together, but what would that sound like beneath a mile of ice ? The old man continued. "The glacier streamed by for thousands of years . The climate warmed ; the ice changed to muddy water , and then disappeared, leaving behind a windy, treeless world . The dust from dried-up rivers  choked the air."
56 EARTH SCIENCE - Glaciation - What is an Ice Age? An Ice Age is when much of the earth's surface lies beneath glacial ice. On at least four separate occasions, separated by tens of thousands of years, ice from Canada advanced southward to cover New England. Evidence of the last two glaciations is widespread at the surface. Evidence of the older ones is buried beneath Long Island, Nantucket Island and MarthaÕs Vineyard.
57 EARTH SCIENCE - Pre-history- When did the Ice Age happen? The glacier began its retreat about 20,000 years ago, and may have reached its outer limit as much as 5000 years earlier. There is no way to date these events exactly.
58 EARTH SCIENCE - Ice thickness - How thick was the glacier? It's true. Even Mount Washington in New Hampshire and Mt. Kahtadin in Maine, two of New England's highest peaks, were buried by ice. They were, however, little affected by the ice. No one knows how thick the ice may have been at its maximum, although estimates range up to one mile thick at the St. Lawrence River, declining to zero at the southern and southeast coasts. Interestingly, all of New England's highest Mountain Ranges -- The Green Mountains, the Adirondacks, the Presidential Range, and the White Mountains -- had their own small valley glaciers, prior to the arrival of ice from Canada, which was called the Laurentide Ice Sheet after the Laurentian Mountains in Quebec.
59 EARTH SCIENCE- Ice Sheet - What is it like on an ice sheet? Most people don't think of deserts as being cold places, but many actually are. Deserts are defined simply on the basis of precipitation, which is very low, astonishing low, in the middle of continental ice sheets. Also, very cold air is dry, hence clouds have difficulty forming. Humans in such climates have to fight desiccation as well as cold in order to survive.
60 EARTH SCIENCE- Black ice - How can ice be black? Most people know that even the clearest ocean becomes dark with depth, and that deep-sea creatures live without light at the ocean bottom. The ocean becomes dark because water absorbs the energy in the visible spectrum. The same happens with glacier ice, which, especially when dirty, is much less opaque than water. It is funny to think of a blinding white glacier surface becoming absolutely black at depth, but it is true. No one, however, can experience the blackness.
61 EARTH SCIENCE - Till - What is it like where ice meets rock? Beneath most glaciers is a wet paste of crushed rocks mixed with rock chunks. When pressed hard against the bed of the glacier and dewatered by the pressure, it becomes a firm solid called "till," which is a Scottish word for a "kind of coarse and obdurate land." This smear of glacial debris is what was called hardpan by the colonists, or pan for short.
62 LITERATURE - Suggestion - Can you get cold just by thinking about something cold? Here we try to bring the reader from the analytical to the sensual. Thinking about cold thick ice and glacial deserts is enough to make anyone cold. We are simply suggesting that the reader do the same.
63 TEACHING - Sense of touch - Are the scratches big enough to feel? Grampa is asking Adam to connect the physical evidence of the glacier scratches with the grating and grinding of the ice, something that Adam can imagine, if he gets the time. This is about physical evidence.
64 LITERATURE - Dust - Why did Grampa blow on the rock? For every scratch on every rock there is little pile (or trail) of dust that ended up in rivers and was blown about by the wind. These concepts will follow. For now, we just want to plant the idea for the reader that dust comes from scratches.
65 LITERATURE - Alliteration - How do glaciers grip a stone? Throughout the text we combine words with complementary, even similar sounds. This is the clearest example of this technique called alliteration.
66 TEACHING- Imagination - What does a glacier sound like? Adam has just made his first "solo" imagined scene. He is taking his information then connecting it with what he has just learned.
67 EARTH SCIENCE - Ice flow - How does an ice sheet move? "Streamed" is indeed the correct word. We are being literal, not metaphorical. Ice does stream by, always moving from the center of the ice sheet towards its margins. Even if the glacier appears to remain the same size and be stationary, it must move forward to keep that shape because the ice melted off the margins must be replaced by fresh snowfall from the interior. Also, an ice sheet this big takes several thousand years to build up, and would continue to drain for at least a thousand years, even if the supply were shut off.
68 EARTH SCIENCE - Climate change - What causes an ice age? The climate is in charge. Although ice sheets do influence the local climate, their size is governed by the global climate. In fact, the growth and shrinkage of the ice sheets was, historically, the first solid evidence that Earth's climate was capable of changing dramatically. Ironically, slight shifts in the receipt of solar radiation in mid latitudes seem to be the factor that triggers the onset and disappearance of ice ages. These shifts are governed by the configuration of the earth relative to the sun; its tilt, the eccentricity of its orbit, and the wobble of its spin axis. Once an ice sheet is large enough, then it begins to be a dominant control on climate.
69 EARTH SCIENCE - Meltwater - What happens when a glacier melts? Rivers draining ice sheets and glaciers are among the most sediment-laden in the world, reaching a concentration of up to 40% by weight of mineral solids. The water comes from ice melt, and the sediment comes from fine particles of ground-up rock called glacial flour that are concentrated within the lower layers of the ice. Usually, glacial water is a battleship gray, but the water can take on the color of the local rocks, sometimes greenish, brownish, or pinkish tones of gray.
70 EARTH SCIENCE - Glacier winds 0 Why is it windy near the ice? Glacier margins are exceptionally windy places for two important reasons. First, during the summer, the abrupt contrast between reflective ice and absorbent land sets up a strong thermal contrast that produces intense winds called katabatic winds. Cold air above the glacier descends continuously towards its margin where it flows beneath the warm air rising above the land. The other reason involves the glacier as a topographic obstacle. Regional winds are pressed against the edge of the ice, then deflected parallel to it, also creating a windy world.
ICE AGE (Blue glacier)
"Grampa paused, transported far, far back in time. He could hear the frigid water rushing through icy caverns  . He could see the glacier melting, leaving the land bleak and bare and brown. He could feel the gusty winds swirling all around him. He gasped for breath as if he were really there , watching the dust settle back to a rocky rubbled earth. "Are you all right?" asked Adam, worried by Grampa's sudden wheezing breaths. "Oh, yes, I'm fine." Grampa eyed the boy uncertainly. "Sometimes those ancient worlds seem so real to me--as rich in sights and sounds and smells as our present one," he confessed. "As if I'd been there once and could go there again. But, of course, that's not possible, is it?" Grampa stopped. His grandson stood speechless ."
71 EARTH SCIENCE- Glacier dust - Why is the glacier margin dusty? Rock flour that is not washed to either the sea or lakes usually comes to rest on the abandoned channels of meltwater streams. The cold air flowing down the glacier is also a dry wind because the air warms as it compresses adibatically (the same thing happens when you pump up a tire), and because of friction. This cold dry wind is especially capable of picking up dust and carrying it long distances. When the dust finally settles, it creates a blanket-like mantle of wind-deposited sediment called loess, an important soil substrate that lies beneath most of the important "breadbasket" areas of the continents, notable the American Midwest, the Ukraine, the Yellow River region of China, and the Pampas of Argentina.
72 TEACHING- Repetition - What does glaciation sound like? This is a replay of what was more carefully described on the previous page. It gives the reader time to pause and absorb, with no new information coming their way. We merely reinforce what was already learned.
73 LITERATURE- Concern - What is it like to choke on dust? Here we invite the reader to become concerned about Grampa, without whom this book could not continue. The reader must ask themselves if Grampa is indeed a little crazy, since he imagines a world so real that he actually coughs.
74 LITERATURE - Surrealism - Can people travel through time? Adam, and most other readers, know, that it is not possible to travel backwards through time. Yet, an important goal of every geologist is to re-create an ancient world so accurately that they seem almost real. Grampa coughs because he has probably experienced dusty glacier winds somewhere in his travels. His memory simply provokes that old stimulus. After being "found out" Grampa asks Adam if it is possible to time travel. Adam's speechless reflection is the clue that tells us that the boy is beginning to catch a glimmer of Grampa's special powers.
TUNDRA LIFE (Mammoths and Caribou)
"Grampa cleared his throat. "Then, out of the dust sprang a spongy green carpet of plants called tundra . Tiny flowers and miniature shrubs hugged the ground  in that cooler, windier world. Caribou grazed in great herds . Woolly brown mammoths  trampled the tundra, waving their trunks in the air." Grampa, with a far-away look in his eyes, cupped his hands behind his ears. "Can you hear them ?" he whispered to the boy. "Hear what?" whispered Adam back, cupping his ears like the old man. "The mammoths," murmured Grampa. The oddest expression crossed over Adam's face. He quickly dropped his hands from his head. For a second, he almost believed that he had heard something, too . "The tundra receded northward  when the climate began to warm . The animals migrated, too , leaving bleached antlers and tusks behind. The trees returned--first spruce and pine, next birch and oak, then finally, all the rest . Their roots cracked the hard, glacial soil, breaking it apart . Dust and leaves mixed together with stones and sand to make a rich, dark soil . The forest filled with woodland creatures--wolves, bears, panthers, possums, and deer ." Adam handed the polished glacier stone to his grandfather. Grampa cradled  the precious black rock in the palm of his hand for just a moment . Then he knelt down and tucked it back in the shady corner. There, in that secret spot, it had rested safely for decades, easy to find whenever he wished. Grampa stood up straight, strangely content. He saw that Adam was staring off into space, still and quiet, as if in a trance. "Was I right to hope that he's ready to learn --to read the stones, to travel through time, to hear the earth  as it talks to me?"
75 ENVIRONMENT - Tundra - What is tundra? Globally, tundra is an important biome, covering nearly as much area as tropical rain forests. It consists of a community of plants adapted to harsh cold conditions, which can be either wet or dry. The isolated tundra communities found locally on the highest New England summits are but tiny remnants of a once extensive treeless world that followed in the wake of the ice. We know that tundra was formerly much more extensive in the northeast because the spores of moss and the pollen from cold-adapted genera of sedges, grasses, and willows, and heather, are abundant in the lowest layers of many bogs. Trees of every kind were absent from these layers, primarily because the climate was too cold, but also because trees re-colonized the landscape at a slower rate.
76 ENVIRONMENT - Prostrate plants - Why are the plants so low? Tundra adapted plants are often prostrate, meaning that they grow very near the ground. During early post-glacial times the wind was much stronger, partly because of the proximity of the glacier, but also because, ironically, there were no trees to stop the wind. The force of the wind increases exponentially above the ground, so tundra plants adopted the strategy of staying very low. Battered trees with misshapen limbs are referred to as krumholz, and are diagnostic of treeline conditions.
77 ENVIRONMENT- Caribou - What are caribou? Caribou (Rangifer tarundus), or reindeer, were once the dominant grazing herbivores in the northeastern seaboard. Living on lichens, saplings, and other herbs, their bones have been found in the oldest firmly dated archaeological sites in the northeast, which extend back to about 11,000 years before present. Today's woodland caribou, which are making a comeback to New England in response to conservation efforts (Rangifer tarundus), are often solitary, and live in small groups. In contrast, the barren-grounds caribou that are now characteristic of tundra regions, and which were once present throughout New England, migrate seasonally to calving grounds in herds that number in the hundreds of thousands of individuals.
78 ENVIRONMENT - Mammoths - What is a woolly mammoth? Although less common than caribou, the woolly mammoth (Mammuthus primigenius) is the signature mammalian species of the ice-age world. It is a member of the elephant family that was larger than the largest African bull elephants. Its tusks curved outward in two directions. Some of its hairs were more than three feet long. Mammoths, which were primarily grazers, co-existed peacefully in New England with their smaller and less spectacular cousins, the mastodons, who survived on a more varied diet. Ironically, the most common mammoth fossils are those dredged up by fishing boats trawling the bottom of the continental shelves, which were dry land as the northeast was being deglaciated.
79 TEACHING - Pretending - Can you hear something in your mind? Grampa reinforces the idea that the ancient world can be experienced sensually if you try hard enough.
80 LITERATURE - Transformation - Is Adam changing? Adam's resolve is weakening. He is beginning to believe that Grampa can actually experience the ancient world, and is embarrassed by having been listening to something that went extinct over 11,000 years ago, except for those on St. Lawrence Island, which survived as an isolated dwarf population until about four thousand years ago.
81 ENVIRONMENT - Eco-zones - What controls plant boundaries? Tundra could survive only in a broad band fronting the ice sheet. Thus the tundra community tracked the ice northward, receding with it.
82 EARTH SCIENCE - Postglacial - What was the early postglacial climate like? Late glacial climates were actually quite complicated. In general, things remained cold until approximately 13,000 years ago (a time period called the Older Dryas, so named for the tundra plant Dryas integrefolia). Then the climate warmed abruptly for about two millennia, during which time the earliest boreal trees arrived and began spreading rapidly. Then, about 12,000 years ago, there was an abrupt return to near glacial climates called the Younger Dryas, which lasted for 500-700 years, during which time the earliest humans seem to have reached New England.
83 ENVIRONMENT - Ice age fauna - Why are the mammoths no longer present? The animals, being dependent on certain plants, had no alternative but to follow the vegetation zones northward. Thus, tundra animals were displaced northward into Canada as southern animals were moving northward into New England. The word migration is technically wrong, because migration usually refers to a seasonal movement in search of habitat or food. The more accurate phrase is "range extension." Essentially, the climate changes the glacier, which changes the land, which changes the plants, which changes the animals, all in sequence. The details are very complex.
84 ENVIRONMENT - Forest history - When did the forests return? Using pollen from bogs and lakes, palynologists (scientists who study fossil pollen) have reconstructed the general pattern of vegetation changes throughout New England. Essentially, the earliest trees were those that were best adapted for cold conditions, notably spruce, pine, and birch. By about 9,000 years, the pollen from deciduous trees, notably oak, became more important than the boreal taxa. Many other deciduous elements -- elm, hickory, chestnut, maple, etc. -- arrived in sequence, each at the rate governed by its seed dispersal.
85 EARTH SCIENCE- Initial soils - Do trees help make the soil? This is both literally and figuratively true. Without plant roots, especially those of trees, the hardpan would have remained hard. But the oncoming trees needed to anchor in firm soil, otherwise they would blow down, and needed to root deeply to get water. This opened up the soil.
86 EARTH SCIENCE - Soil formation - What is soil made of? This statement gives the recipe for soil. The dust refers to the windblown silt that was so widespread during deglaciation. Leaves, when decomposed, provide the humus required for fertile soils. The stones of glacial origin were already there, and would gradually be buried by a finer-grained topsoil produced largely by biological activity, especially the work of ants, grubs, and small mammals. It took several thousand years to produce a good, thick soil.
87 ENVIRONMENT - Forest animals- Did wolves and panthers used to live here? The woodland creatures, especially the signature species mentioned here, arrived with the forest. All were prominent when the colonists first arrived, as were rattlesnakes, which we left out of the list because the others are all mammals. Yet many were rendered locally extinct by hunting. Wolves, bears, and panthers, being large predators capable of taking livestock, were intentionally killed by the settlers. Whitetail deer, of course, now thrive in the absence of predation by these carnivores.
88 LITERATURE - Symbolism - Why is the rock so important to Grampa? Precious is not too strong a word for the small scratched rock because it symbolizes everything to do with the ice age. Cradling it in his hand for just a moment is a deliberate prayerful act. Putting it back physically is our way of informing the reader that we will now move forward in earth history.
89 LITERATURE - Transformation - What is happening to Adam? Here we suggest to the reader that Adam has moved past the previous stage in his understanding. Grampa no longer has to tell him to imagine something, for it is becoming automatic to Adam.
90 TEACHING - Listening - Why are they always listening? We emphasize the hearing and listening done by Adam and Grampa in this story. This is our way of reinforcing those who have the story read to them. By listening carefully for the call of the mammoths, or the ice age winds, or the rushing of rivers, etc., we expect them to be listening to the story as well.
WALKING THE WALL
"Wordlessly, the two headed through woods toward the opposite corner of the abandoned meadow . Along the way, a giant green hemlock lay uprooted, completely blocking the path . Grampa detoured deeper into the woods around the tangled, soil-clinging roots. Adam chose a different path ; he scrambled up on a nearby stone wall, following it like a rocky road. The stones shifted beneath his feet, so he concentrated on each step, never losing his balance. He was about to jump down when something out of the ordinary caught his eye. It was a stone, dull and dusky red on one side, gray on the other. He slid off the wall, lifted the unusual stone with both hands, and lugged it to the nearby path . "What's this?" he demanded , dropping it on the grass in front of his grandfather. Grampa bent down for a closer look. "That's a campfire stone . See how it has been scorched rusty red on the outside, then shattered by the fire's heat ?" Adam flipped the stone over in the grass, examining each side. Grampa explained with a touch of excitement, "This rock tells many tales . Its crystals were made millions of years in the past; its shape is glacial, from the last ice age. And its home is now a wall built two centuries ago."
91 TEACHING - Movement- Is their farm square? Here we give the reader the idea that our walk is following a pattern, and reinforce the idea, formerly stated explicitly, that the meadows are now reforested.
92 LITERATURE - Obstacle - Did the falling tree hurt the wall? Trees that come to reclaim an abandoned meadow do not last forever. The fallen tree also symbolizes one of life's little hurdles, an obstacle that creates an opportunity, because choices have to be made. It also reminds us that stone walls are helpless in the face of great power, like falling trees.
93 LITERATURE - Free choice - Why didn't Adam follow Grampa? Here we reinforce Adam's individuality, and his increasing confidence in making his own choices, rather than following his Grampa meekly. Like Adam, it is only by making choices that we define our individuality.
94 TEACHING - Physicality- How heavy was the rock? Here we give Adam a chance to be very physical, doing something that most children would do naturally. We must learn physically, as well as mentally and emotionally.
95 TEACHING - Taking charge - Why is Adam so demanding? Adam is now in the process of taking charge of his own learning. Whereas rocks were formerly part of his background, they are now objects deserving of scrutiny. Unusual stones now catch Adam's attention. He is also invested in the idea of learning from the stones because now it is he that demands an answer, rather than his Grampa.
96 TEACHING - Backing off - Why didn't Grampa say more? As Adam's understanding increases, and as Adam begins to initiate these encounters, Grampa's role changes from that of provocateur to that of a source of information. Grampa's explanation is matter of fact, although he does draw attention to the tangible evidence of the fireÕs heat.
97 ARCHAEOLOGY - Fire-cracked rock - Why do rocks redden and crack? Campfire stones, or "fire-cracked rocks." often have these two distinctive features. First, the heat of a campfire, when combined with the availability of oxygen, causes oxidation of the iron-bearing (often black) minerals in each stone, a process that imparts a red color to the stone. The same thing happens when bricks are baked; the mud changes from gray to brick red. The shattering happens next. Silicate rock is a very poor conductor of heat. Thus, when heat is rapidly applied to the outside of a stone the outside layer expands long before the middle of the stone is able to do the same. The consequence is that the side of the stone nearest the fire will expand away from the core of the stone, shattering in the process.
98 EARTH SCIENCE - Attributes - How can a rock have many stories? This is one of the more complicated lines in the book. It isn't that the entire stone has an age. Rather, different attributes of the stone have different ages. The composition (meaning its mineralogy) is Paleozoic, dating from the time when Iapetos closed and New England lay beneath large mountains. The shape, whether fractured, scratched, or ground down, is of glacial origin. Its position is historic.
FOSSIL CAMPFIRE (Paleoindians)
"But what about the campfire? When  was that?" interrupted Adam. "Sometime after the ice. Exactly when, I donÕt know. But people did live here. They crouched around a crackling fire, heating their hands near the flames  . And, if they were lucky, they breathed in air that smelled of roasting meat and corn, while their children played nearby . They sang their songs, they told their tales, uttering sounds and sentences lost to a misty past. But they left this special stone behind, and it speaks for them today ." Adam already knew about the Indians who were here when the Pilgrims landed . He had read about their villages of bark-covered long-houses, and about their clothing and canoes. He also knew something about their ancient ancestors, the original Americans , who had lived here for hundreds of generations before the written word. Adam had learned about this earlier story from his mother's collection of stone artifacts, which she recently gave to a museum . What he now realized was that these primitive tools were also special stones, fashioned not by ancient beaches or grinding glaciers, but by people long ago . The oldest tools in her collection were like long flint knives. They were used by nomads--Paleoindians --who ambushed caribou with their stone-tipped spears in an almost-tundra world. Next came village-dwellers--Archaics  --who hunted deer with bow and arrow, and who speared fish in flowing streams. Finally came the larger tribes--Woodland Indians  --who planted crops with blunt stone hoes and who stewed their food in fired clay pots."
99 ARCHAEOLOGY- Dating techniques - How can you date a rock? This fire-cracked rock is probably a genuine Indian artifact, perhaps the only one that is likely to find its way into a stone wall (the fire could have taken place after European settlement). Grampa doesn't know when the reddening took place, although he does know that there is a geological dating technique -- thermoluminescence -- that can determine when the rock was baked.
100 LITERATURE - Description - What did Woodland Indians eat? Here we try to engage each of the senses. Crackling fire (sound), heating their hands (touch), flames (sight), roasting meat and corn (smell and taste). We are also trying to convey the sense that these humans, like the earlier mammals, live close to the land.
101 SOCIETY - Ancient play - Were the Indians primitive? We are trying to reinforce that this was a complex society that left the physical evidence in stone, not just a band of hunters. There were children and families, language, music, traditions, almost none of which can fossilize. These societies were as complex as those of Europeans, even though they did not use writing to document their culture.
102 SOCIETY - Extinct Languages - What did their language sound like? Students can be taught to hear the stories told by stones. In this case, we are deliberately contrasting the lost language of the Native Americans with the discovered language of the stones. This is also our way of pointing out that archaeology and geology will speak forever.
103 HISTORY - Contact tribes - What kind of Indians meet? Although the northeastern coast had been explored prior to 1620, the arrival of the Pilgrims on the Mayflower at Plymouth marked the first permanent British settlement in New England. First-hand accounts of the "savages" are described in their journals and reports; these writings separate the disciplines of prehistoric archaeology from history. The variety of Indian tribes present at the time of "contact" were derived from a common Algonquin heritage, as evidenced by their artifacts, linguistics, and now, by DNA sequencing.
104 ARCHAEOLOGY - Early Man - How long had the Indians lived here? Estimates for the date at which Americans first arrived in the northeastern north America, and the means by which they obtained their livings, remain highly controversial, especially with the general acceptance of a maritime site in southern Chile called Monte Verde, which clearly dates to something in excess of 12,000 years old. Prior to this discovery, it was generally believed that the earliest Americans crossed the Bering Land Bridge on foot in search of big game no earlier than about 11,500 years before present, the radiocarbon age for the oldest well-dated, so-called "Clovis" projectile points.
105 SOCIETY- Gender roles - Did she collect the artifacts? Here we illustrate that a fascination with the natural world is a family tradition, now spanning three generations and being pursued by both male and females. Adam learned this from his mother. Later, we learn that Grampa learned much from his sister. Males in this family do not have a monopoly on learning.
106 ARCHAEOLOGY - Museums - Why did she give the artifacts away? Important relics belong in museums where they can be safely guarded and hopefully appreciated by the general public. Provided that ethnic traditions are honored, the archaeological past is a common trust.
107 ENVIRONMENT - Human agency - Do humans modify stones too? Here we drive home the point that that the human modifications of stone are, at least fundamentally, no different from other earthly agencies and processes. We are all players on the same scene. This "eureka" moment for Adam is a critical step towards his understanding that humans are part of the earth, not owners of it.
108 ARCHAEOLOGY - Paleo-indians - Who were the Paleoindians? This paragraph spans the full range of northeastern archaeology, a field with an enormous literature, and many controversies. Here we point out only a few important facts relevant to the text. Our stone "tools...like long flint knives" are the so-called Clovis points, which are fluted, meaning that a large flake was struck longitudinally off the base of the point, presumably in order to more easily attach (or haft) them to wooden spears. Their makers, the Paleoindians, arrived in New England prior to 10,500 years ago, and are known to have hunted caribou and sea mammals, as staple foods.
109 ARCHAEOLOGY - Archaic tribes - Who were the Archaics? By "Archaic" we mean a series of clearly defined archaeological traditions called Early, Middle, and Late Archaic, which span the interval from about 9000 years to about 2000 years before present. Their stone technology was highly varied, with carefully crafted arrowheads, scrapers, fishhooks, cleavers, adzes, spear points, etc., and their sites often indicate re-use and intense occupation. They traveled and traded widely throughout the northeast, subsisting largely on forest mammals (especially white tail deer), fish, and shellfish. They were the ancestors of all known northeastern tribes.
110 ARCHAEOLOGY - Woodland tribes - Who were the Woodland Indians? By "Woodland Indian" we mean those Indian groups during the last several thousand years that lived in permanent villages, whose remains are generally associated with New World agriculture (maize, beans, squash, etc.), ceramics and whose traditions extended forward in time to that of the first European contact. The Woodland Period ended and the Contact Period began when Europeans established contact with the Indians, because their material culture changed so dramatically.
TAKING THE FOREST (deforestation and farm conversion)
"The ancestors of Adam's adoptive family , and other settlers, were next in line . They also left their stones and tools and bones. Of course, they left a written history too, so more is known about them . These colonists from Europe changed the wilderness from forest into farm. They chopped down acre after acre of tall timber, burning the trees in bonfires that glowed orange and red through long days and nights. Oxen bellowed and clanked their chains as they tore the stumps from the ground. Man and beast worked as a team to change the world forever . Holding his red-scorched stone with both hands, Adam headed back to the wall. He searched for a gap where his prize could be safely hidden, as though it were a precious relic . Within a minute he was back on the path with his grandfather. They walked side by side, stopping here and there to patch the wall with fallen stone. The old meadow rose high enough so that they could see the landscape below them. Hunting parties no longer traveled through primeval forests ; instead, a patchwork  of former farms, with stone-rimmed fields covered the countryside. "Did you build any of those walls all by yourself?" asked Adam. He hadn't realized how many stone walls existed in their little corner of the earth . "Just those two--the ones near the pond," answered the old man wistfully, pointing his arm like a rifle. "But, of course, I helped build others, adding my stones to the ones already there ." Scenes from his childhood flashed through his mind, sparked by the sight of the walls he helped build. The farm had been a busy place then , with its grassy green pastures dotted large with cows and small with sheep. The corn rustled tall in the summer breeze, growing so fast that it squeaked. Pumpkin leaves smothered the ground with humid shade. Apple trees dropped their juicy gifts from above. And the barn stood red and straight, stuffed full of sweet-smelling hay."
111 SOCIETY - Adoption - Why was Adam adopted? This is the first and only place in the book where Adam's history as an adopted child is mentioned. Up to this point, the reader has probably seen that Adam's genetic makeup is different from that of his Grampa, and may have assumed that his different appearance was due to intermarriage either between Grampa and his wife, or between one of his children and someone from another race. Now that we know that Adam is adopted, we understand that the values in this book transcend those of blood ties. This book is about an adopted person but is not about adoption. We do not answer the question of why Adam was adopted because it is irrelevant to the book.
112 HISTORY - Continuity - Is history the story of one group after another? We use the phrase "next in line" to emphasize that the pre-human history, the prehistoric human history, and the historic human history are all part of the same story. Here we emphasize that the connection between natural history, archaeology, and history is a seamless one. That the agencies of each time period, regardless of whether they are sentient beings, all take place on the earth, and leave their mark on the stones.
113 ARCHAEOLOGY - Historical - Why pursue archaeology during the historical period? A vital discipline known as Historical Archaeology uses the tangible, physical record of human activity to complement written history. Recovered objects often involve the everyday mundane activities by common people. In contrast, written history is usually about important people or notable events. Historical archaeology fills in the picture. Stone walls can be considered artifacts.
114 ENVIRONMENT - Catastrophe- How could humans change the world? So important was the introduction of European culture to the Americas that it is now referred to as the Columbian Invasion. The demography, ethnicity, diseases, and culture of Native America were greatly changed, many would say for the worse. The local extinction of animals and the introduction of exotic new ones were also important events. Most of this change resulted from loss of habitat during the removal of the forest.
115 LITERATURE - Imitation - Why did Adam hide his stone? Adam merely does what Grampa did with the glacier stone. If the old man can be reverent about the earth and its stories, then so can Adam. This is the first visible sign of Adam's nascent appreciation for geology.
116 ENVIRONMENT - Forest history - Do primeval forests exist? There is really no such thing as a forest primeval. The pollen record indicates that the forests were always changing during the previous 10,000 years as new immigrant taxa arrived, as the climate changed, and as pathogens swept over the countryside, such as the ones that caused the hemlock decline over 6000 years ago, or the 20th century blights of Chestnuts and Elms. There is no question that many of the original trees, especially the pines, were enormous, and that the secondary growth is smaller by comparison. Human changes were superimposed on more subtle natural changes.
117 ENVIRONMENT - Mosaic ecosystem - Is the ecosystem more varied with walls? Patchwork is the correct word. Enclosures were generally built in the shape of a square or a rectangular, and intersected each other often at right angles. And the stone accumulating in the fields was moved outward into piles which eventually grew into walls. Each wall, being dry, is like a local desert which serves to differentiate the habitat much more complexly than was the case without the stone.
118 STONE WALLS - Abundance - Are stone walls considered landforms? The number of stone walls is truly astonishing, especially since it is difficult to see more than several at a time. In some places the walls are important landforms, and can be easily recognized from the air. They are now an integral part of the environment.
119 STONE WALLS - Accumulation - Did walls accumulate gradually? As Grampa states, walls typically grew in two entirely different ways. Most often, the walls simply grew higher and more massive over the years as the supply of unwanted fieldstone continued to grow. At one point, the walls held fence posts with several rails. Eventually the walls grew up to replace some or all of the rails. Many times, however, new walls were built from scratch using the linear stone piles already there.
120 HISTORY - Farm economy - When did New England farms decline? Working farms, meaning those that actually turn a profit from agricultural activities, continue to disappear across New England. Every day, another one goes out of business. The rural landscape described here, with its several kinds of livestock, hay, corn, pumpkins and apples, is nearly gone. In its place are special interest farms such as organic or community farms, as well as the many part-time hobby farms on which living expenses come from outside revenue.
GRAMPA'S TRICK (He pushes over a few stones)
"Grandfather and grandson worked their way downhill, stopping here and there to stack loose stones back in place. Within minutes, however, they discovered a tumbled section of the wall that needed to be rebuilt . At first, Adam thought the job was impossible, because the stones kept sliding back down, almost smashing his toes. But soon he learned the trick . He laid one stone on two, and two on one, layer after layer. He chinked them up on the outside so they tilted towards the middle . "Looks like that will hold for now," said the boy proudly as he hefted a stone to the top of the wall. That finished the job, so he turned away from Grampa, who was on the other side of the wall. Moments later, from behind him came the crashing sound of falling stones. Adam whirled around, eyes wide with surprise. There, on the ground, lay the last of the stones he had just replaced. "I'll have to square them away more carefully this time," he scolded himself. That's when the old one decided to pop up from behind the wall, grinning mischievously from ear to ear. Adam realized immediately that he'd been tricked! Grampa himself had knocked over the stones. "Grampa!" he wailed, in exasperation. "All right, all right!" Grampa chuckled. Then the two of them quickly set to work repairing the fallen stones. He didn't tell Adam that someone had played the same joke on him a half century earlier  . Before long, they lifted the last stone into place . Their tour though time was nearly done, but Grampa had saved something wonderful for the way home. With the old man in the lead, they set off in the direction of the farmhouse  , stopping in a field deeply shaded by paper birches ."
121 STONE WALLS - Tumbled - Why do walls fall down? Tumbled sections are actually quite common, and derive from three basic processes. Most common is the gap created by the collision of a stone wall with a tree felled by a storm, disease, or simply old age. Second is the movement of soil below the wall whether by the heaving of frost, the erosion of soil, or the burrowing of animals. Finally is the failure of the stacking, which may have been originally good, but which may have changed as the stones shifted against each other. The point is that with so many miles of wall, a section of it is bound to fail here and there, now and then.
122 TEACHING - Trial and error - Why didnÕt Adam ask what to do? Sometimes there is no substitute for learning a job through trial and error. Adam is taking on more responsibility here, and is now doing a significant part of the job.
123 STONE WALLS - Architecture- How is a stone wall built? This is the basic formula for the construction of a stone wall, especially when slab shaped stones are used. Like bricks, the stones must be laid so that the spaces between abutting stones in one tier do not continue into the tier above them. Usually the widest sections of each stone are placed on the outside, and the stones are tilted inward towards each other. When gravitational settling occurs, which it surely must, the tilted stones will settle against each other, adding strength, rather than taking it away.
124 LITERATURE - Humor - Is Grampa a practical joker? This has been a rather serious book, up to now. We felt that at this point in the story a little levity would help break up the tone. But there is also a hidden symbol in the work of Grampa's actions. Humans not only build walls, but destroy them as well. This brings us back to the opening and closing scenes of the book, in which case one wall must be sacrificed to build another.
125 LITERATURE - Teamwork - Is it better to work together? Emphasis here is on the word "they." Lasting bonds between people often result when they work together on a project of mutual interest. Here the boy is not too young, nor Grampa too old, to do a "man's" job. This is our symbolic way of saying that grandfather and grandson can work together to help bridge the generations.
126 LITERATURE - Direction - Are they finally heading home? This is a literary device that we use to tell the reader to stay with us just a little longer. We are heading home, with only one stop remaining. We are also informing the reader that this story has a beginning and ending in the same place, the house.
127 LITERATURE - Allusion - Why go into a darkly shaded place? Here we do two things. First, we are alluding to the fact that our final secret will be obscured in some way. Secondly, we identify a different type of tree just to add variety. We have already discussed pines, hemlocks, oaks, and apple trees.
FROM OUTER SPACE (Finding the meteorite)
"Stones, like those the stonemason hoped to buy , bordered the former pasture. Beginning in one corner, Grampa marched like a stiff-legged soldier, thirty-two paces  beside the wall, beckoning Adam to follow. He explained nothing. He simply directed Adam to help him clear away a pile of rotting brush, promising mysteriously that it would prove worthwhile. Adam's arms began to ache, and he was about to complain  when an astonishing sight froze the words in his throat. "Is it what I think it is? A meteorite ?" asked Adam. He had seen a meteorite before, on a school trip to the planetarium . His hands touched the cold, pitted surface of a half-buried boulder, partly hidden by ferns. "Exactly," said the old man proudly as if it were the largest diamond  in the world. "This boulder is a family secret . It once was a shooting star . You can see where the metal melted and bubbled as it burned  its way to the to the ground ." "I wish I could have seen it fall!" cried Adam, automatically shifting his gaze skyward . "It fell long before your time, or mine," said Grampa. "But not here. The glacier carried it from someplace else , maybe a hundred miles away, and dumped it here on our land. It might have even landed hot on the ice , before being buried in the snow. I reckon a museum would pay a hefty sum for such a fine specimen ."
128 LITERATURE - Potential loss - Would Adam sell these stones? By saying "similar to those the stone mason hoped to buy" we are making it clear that any or all of the stones may have hidden value. What loss might result if the stones were sold? Indeed, if they were already sold, then we could not find the most important secret of all.
129 LITERATURE - Precision - Why pace out a distance? Grampa must carefully measure the distance by taking exact steps and counting them exactly. This is a hint that the final secret is well hidden.
130 TEACHING - Patience - What could be worth so much work? Patience pays off. Sometimes children just have to do what they are told, and not complain about it. Sometimes, in teaching and parenting, there is simply no substitute for authority.
131. TEACHING - Confidence - Is Adam correct? Is it a meteorite? Adam has gained confidence. He no longer has to be prodded by Grampa. Astonished as he is, he can identify this special stone, clearly the most important one of the afternoon.
132 EARTH SCIENCE- Meteorite - What is a meteorite? Technically, a meteorite is a rock that came from elsewhere in the solar system before falling through the earth's atmosphere. Most of these rocks lie in the asteroid belt, which lies between Mars and Jupiter, and were launched into space during planetary collisions. Generally speaking, there are three kinds of meteorites. The iron meteorites are very heavy, composed principally of an iron-nickel alloy, and represent the centers of exploded planets and planetismals that were launched into space during the formation of our solar system, and have been orbiting since then. The so called "stony" meteorites or "stony-irons" as they are sometimes called are, like the earth's crust and mantle, composed of silicate rock. The rarest are the carbonaceous chrondrites, which include organic compounds.
133 EARTH SCIENCE - Meteorites rarity - How much is a meteorite worth? The comparison with a diamond, in terms of monetary value, is not too far off. Meteorites, especially large ones, are extremely expensive, and reside in museums where they are proudly exhibited. Pound for pound, diamonds are more valuable, but none could be as large as this meteorite.
134 LITERATURE - Family secret - How long has the meterorite been a secret? This is the final secret of the book in terms of the geology. And it is the only family secret in the book. By keeping, rather than selling the stone, the family demonstrates that it values the land. Its location is passed down through the generations.
135 STONE WALLS - Shooting star - Could I find one of these in a wall? Robert Frost wrote a poem titled "A Star in a Stoneboat" that captured the same sentiment here. The star was a shooting star, which is the trail of visible light caused by the burning of debris from the planetary fragment as it descends through the atmosphere. Shooting stars, technically called meteors, do not last long because they travel at extremely high velocities measured in miles per second, rather than miles per hour. The largest meteorites have a relatively constant entry velocity into the earth of about 15 miles per second. That's fast enough to cross the United States from Atlantic to Pacific in a few minutes.
136 EARTH SCIENCE - Meteor - Does a shooting star really burn? Technically, the material doesn't burn. The more precise term is "ablate." In this process, atoms are stripped off the speeding meteor due to friction with the earth's atmosphere, and in the process, generate extremely high temperatures at the edge of the fragment, temperatures hot enough to produce light in the visible spectrum. Rarely, there are bubbles, but most of the irregular "bubble-like" cavities are flutes, where the ablation of the metal surface was particularly effective.
137 EARTH SCIENCE - Meteorite impact - Do meteorites actually hit the ground? Meteorites do hit the ground, often exploding into fragments in the process. A direct hit would certainly kill a person, but the odds of being struck are negligible. Once in a while, however, a fragment penetrates the roof of house. In one famous case in Wethersfield, CT, a meteorite came through the roof of a house and richocheted around the living room before coming to rest.
138 LITERATURE - Expectations - Why does Adam look up during the day? By looking skyward, Adam is connecting not only the tangible meteorite with an ephemeral event, but is also connecting the past with the future. If meteorites have fallen in the past, then they will continue to do so in the future. Past, present, and future are, in terms of geological processes, one and the same.
139 EARTH SCIENCE - Antarctica - Where are meteorites often found? Most meteorites known today came from Antarctica, but this is only because they are so easy to spot there, where they are concentrated by melting ice. This meteorite was dumped by the Larentide Ice Sheet before it melted, just as those are being dumped by the Antarctic Ice Sheet today. Millions once lay out there, but they were (and are) quickly rusted in our forest soils, and are difficult to find because they are rare rocks amidst millions of ordinary ones. Big ones, like this one, do survive.
140 LITERATURE - Contrast - How can it stay hot on the ice? A meteorite is traveling so fast, and its edges burn away, so that it does not have a chance to heat up in the middle. Thus, even though the edges are extremely hot, they never are hot enough to melt themselves downward, or burn anything. Additionally, we allude here to another one of Robert Frost's poems in which he asks whether the world will end in fire or ice, the meteorite bombardment or another ice age?
141 SOCIETY - Conservation - Why don't they sell the meteorite? Adam's family kept the meteorite on their farm, in the field, knowing that it was worth a lot of money. This means that their tendency towards conservation is a family value, one passed through many generations. We imply that it has been in the family "long before your time or mine."
CREATION (Earth, Moon, and Meteorite)
"Grampa leaned back against the bronze-black rock, letting the sunbeams soak in . He shut his eyes, reminded of that clear August evening  with his sister when streaks of stardust blazed through the dark night sky. It was there, flat on his back in the field by the pond, that he had watched his first meteor shower, awestruck. There were so many stars--too many to count--and they were so very far away . That night his sister pointed at a distant spot in the sky. She told him  that he'd been born out there and then brought to earth by a falling star. He was so young then, he almost believed her. In fact, she insisted he owed his life to the shooting stars. Later, much later, he learned that his sister's ideas weren't really so far-fetched, that every atom in his body had first arrived on earth that same way  . Grampa explained this all to Adam. Keeping his eyes closed to protect them from the sunlight, the old man spoke about the sun, the moon, the stars, and how everything all began. How leftover pieces still in orbit will fall for eons to come. How fragments like their meteorite collided and crashed and collected in space until all the planets were born. How leftover pieces  still in orbit will fall for eons to come. How a meteorite miles across slammed into the earth ending, some say, the reign of the dinosaurs . And, finally, how someday, perhaps, another big one may fall, bringing unknown changes to that future world . A little later, when he slowly opened his eyes, he realized he was alone. Had his words gone unheard ?"
142 LITERATURE - Integration - Is Grampa dreaming? Even now, always, every human being is influenced by the solar system, Here Grampa lies between two stellar objects, one stone cold, the other radiant with thermonuclear energy. By saying "sunbeams soak in" we allude to radiation, which is the way in which the solar energy reaches us through the vast emptiness of space.
143 EARTH SCIENCE - Perseid Shower - Why is August special for meteorites? Every August the earth's orbit reaches into a belt of small asteroids that causes what is known as the Perseid Meteor Shower. It is the time of year when shooting stars are most easily seen from the northeastern United States. Each streak of light is that of a small object burning up in the atmosphere.
144 LITERATURE - Universal - How far away is the farthest star? We are building towards the most important point of our story, that everything in the universe, no matter how far away, is connected by a common origin, often referred to as the Big Bang, which took place between ten and fifteen billion years ago.
145 SOCIETY - Sisters - Did Grampa learn from his sister? Grampa is the archetype wise person, in this case a male. Here we plant the idea that females can be just as wise, if not even wiser. Grampa is now teaching Adam, but at one point it was Grampa's sister doing the teaching. After all, she was correct in her statement that "he had been born out there," although we did leave out a few details.
146 EARTH SCIENCE - Earth origin - What caused the solar system? We are made of star stuff. All of the carbon, silicon, iron, oxygen,...everything... was made in stellar furnaces, then broadcast throughout space in supernovae explosions. Some of that stellar dust congealed into a solar system in which planet earth came together as originally as cold dust and planetismals. Grampa the spirit, or consciousness, may not have been born out there. But Grampa the physical specimen was. The elements from which he is made have been recycled through oceans and mountains and fossils for all of geological time. Some of each of us was once used by a Paleozoic trilobite, a Mesozoic dinosaur, or a Cenozoic coral.
147 EARTH SCIENCE - Earliest earth - What was the earliest earth like? Very early in earth history, the rain of meteorites was very intense, and the earth was hit with so many meteorites that it was bubbling with molten rock, melted by the heat associated with the many impacts. When the craters and liquid rock cooled, the earth looked not unlike the moon. Earth's scars have since been healed by weathering and tectonic recycling, whereas those of the moon have not. Sometime about 4 billion years ago the frequency of meteorite impacts dropped significantly. But the cosmic cleanup is not over. It continues even today, with earth's gravity pulling in a leftover piece, although large impacts are exceedingly rare.
148 EARTH SCIENCE - Extinction - Did an asteroid hit the dinosaurs? A very large asteroid or comet struck the earth in what is now the Yucatan Peninsula exactly sixty five million years ago, producing an enormous, largely hidden, crater called the Chixalub Crater. This event had global significance, producing tsunamis, shock waves, global fires, darkness, a changed climate, and an increased concentration of toxic metals, and coincided with the extinction of the dinosaurs. Although the details are still debated, many scientists now believe that it was the impact that caused the dinosaur's extinction, opening the way for mammals eventually to flourish in the next geologic era, the Cenozoic.
149 EARTH SCIENCE - Future earth - Will an asteroid hit the earth again? The dinosaur-asteroid connection suggests that something may happen in the near geological future, a logical premise that is enacted by the recent hit movie "Armageddon," which is a biblical metaphor for the final decisive battle between good and evil, which is also common fodder for the "end of the world" doomsdayers. The impact of a future asteroid impact cannot be reliably determined. But it is a certain fact that one will hit earth again, and cause dramatic consequences. Humans, it seems, are not in charge after all, at least at this scale of time and space.
150 LITERATURE - Need to know - Should Adam know about the end of the world? Perhaps our "end of the world scenario" is simply too much for someone of AdamÕs age. Perhaps the extraterrestial origin of our bodies is also too much for a child to deal with. Here we allow the physical separation of Adam from Grampa, so the story can be told without the child needing to hear it all.
"From a distance  , Adam called out loudly. Grampa hurried onward until he arrived at an old storage shed that sagged under the weight of a century . Adam was standing inside on a stout, wooden sled. "Look," said Adam. "It's your stone boat , Grampa. " Grampa paused for a moment. The sled was full of memories, instead of stones . "I remember  the day when my sister and I helped Great-Uncle Cyrus clear the fields--a chore he did each spring. We hitched horses to this boat, and headed for the open fields. There, in an ocean of mud, we fished out stone after stone, and thunked 'em down. When the pile was high enough, we climbed aboard before Cyrus shouted, 'Gid-up now. Go, Sue!' Then away we went, skidding and slipping to the edge of the field. I was the captain, docking the boat, filled with a harvest of stone . "Then, while the horses caught their breath, we jumped off the boat, picked up the stones, and stacked them into place, one by one. Big ones on the bottom, small ones on top ." "Why did you pick just a few loads each year?" asked Adam. "I asked the same thing myself when I was a boy," replied Grampa. "And I didn't get much of an answer  . During lunch with the men in the field--milk, cornbread, and strawberry jam--Cyrus told me that there were very few stones in the early years. And then, suddenly, stones started popping up everywhere. Some folks thought the Devil had put them in the ground. Other folks swore that the stones sprouted from seed. You know what they called them? New England potatoes!" Grampa laughed. He then told Adam what really happened . With the trees gone, the topsoil thinned and the ground froze deeper than ever before. Left by the glacier, stones that hadn't seen the light of day for thousands of years heaved to the surface and had to be hauled away. Like the farmers before him, Grampa had to put the stones somewhere, so he, too, stacked them onto walls. As the walls rose up, they became more than long piles of stone. Some walls divided fields while others marked boundary lines. Some grew high enough to fence in wayward sheep or cows. The nicest walls--those near the house--were works of art. Every wall had a story of its own . "Let's get on home," suggested Grampa, as Adam jumped off the stone boat. "I'm hungry. It's awfully late for lunch."
151 LITERATURE - Independence - Why did Adam wander off? Here we use physical distance, a gap in the story between what Adam heard and did not hear, and a shift in attention from stones to historic objects to help move the story from environmental history to human history. Additionally, Adam's solo adventure symbolizes his growing independence, and confidence.
152 HISTORY - Abandonment - Why did their farm go under? As commercial farms based on traditional animal husbandry began to disappear in New England, some of the first things to be neglected were the outbuildings. Left untended, they simply fell apart. This phrase also helps us move Grampa backwards in age from the present to when he was a boy.
153 STONE WALLS - Stone boat - What is a stone boat? Does it float? A stout wooden sled used to haul stones on old farmsteads was often called a stone boat. Wheeled carts, especially with narrow wheels on muddy fields, would have been far less effective because, given the weight of a load of stone, they would have sunk too deeply into the soil. Adam uses the possessive adjective "your" because Grampa has either told him or shown him this object before.
154 HISTORY - Rock clearing - Did Grampa build many walls? Rock clearing from fields was still going on when Grampa was a young boy in the early years of the 20th century. In other words, the fields were still in production, and needed to kept clear. However, Grampa has not used the stone boat as an adult, because he is not a farmer. Instead he is a geologist (although we are never told that) who merely lived upon and kept the family farm.
155 LITERATURE - Family stories- Is the story of Uncle Cyrus a true one? It is important for Adam to hear these family stories, especially this one, because it involves a child helping someone who is not a blood relative, and who is two generations older. We chose not make Cyrus the father or the grandfather of Grampa. What Adam is doing, at least ostensibly, must be seen as something that this family has always done. He must be able to identify with Grampa as is he were his age.
156 LITERATURE - Metaphor - How can you "harvest" stone if it wasnÕt planted? By "harvest of stone" we mean that the stone was a crop that kept coming, something that needed to be brought in each year. We are also hinting at the connection between life and non-life here, that, fundamentally, they are one in the same. Farmers had to reap the stones because they were the ones that sowed the conditions that led to the problem.
157 STONE WALLS - Construction - How do you build a stone wall? This is how it was actually done, something that can be seen in nearly any stone wall, especially those bordering fields. Besides being almost too heavy to lift, the big stones served as a foundation for those above them. Sometimes, when the walls got extra attention, a large, flat stone was placed at the top to hold it all together. These are called capstones.
158 ENVIRONMENT - Consequences - What did they know about "appearing" stones? By saying he "did not get much of an answer" Grampa is hinting that he plans to give Adam a good answer, two generations later. Grampa is basically saying that he figured this out himself. This is one of the few places in our text that focuses on the explicit details of a geological process.
159 TEACHING - Cause-effect - Is there a scientific explanation? This is our way of contrasting the "pre-scientific" with scientific explanations, which involved cause and effect. It is the only time in the story that we digress into a technical, step-by-step explanation. We do so to illustrate unanticipated consequences.
160 ENVIRONMENT - Fieldstone - How did stone become litter in the fields? This paragraph, in nutshell, describes the physical epistemology of stone walls. Where the stone came from, why it littered fields, why they had to be hauled away, why the walls started crudely, and why they eventually became seen as fences. Every step of this process can be explained in detail. Most important, however, is to understand that clearing the trees changed the soil profoundly, changes that would lead, indirectly, to a concentration of stone on the surface. Stated another way, the farmers were not the undeserving recipient of the curse of stones. Rather, the stones were the result of processes set in motion by the colonial lifestyle. Basically, the loss of the insulating mulch and the compaction by livestock increased the depth of frost, which, in turn, increased the efficacy of frost heave as a mechanism for lifting stones, and, simultaneously caused greater surface erosion to take place each spring. Frost heave works by lifting individual stones up with the expanding, upfreezing soil, but then not allowing them to settle completely during the spring thaw; thus each stone is jacked up incrementally over the years until it is finally exposed. This is why there were not so many stones in the beginning; then they came in a flood.
ADAM'S KNOWING LOOK (Reproduction of title page)
"They left the musty shed behind  and followed a sun-dappled path towards home. Adam began to notice  how many different kinds of walls there were. Square flat stones built tall straight walls. Rounded ones made tumbled rows. Sometimes the stones were black or rust or white or silver, but most were plain and gray. Crusty lichens  and velvety moss colored the stones with patches of yellow and green. Birds and bugs, squirrels and spiders, chipmunks and children--every creature loved the old stone walls . The pair wandered along the forest path, the younger following in the footsteps of the older one. With each step, the lessons of the day became clearer to Adam, taking root more firmly than either of them could have predicted. Grampa had been showing him something important  all morning: that the past, the present, and the future were alive in every stone; that his history, his family's history, and the history of the peoples who'd lived here before them were connected to the stones. The walls were like a library  , stacked high with earthen books. Each stone contained a story of time and place now gone--an older story of oceans, mountains, glaciers, and native peoples who left their mark on the land. And each wall also told a younger story--of Yankee pioneers and their descendants, like Grampa, and Adam himself."
161 LITERATURE - Transition - Why was the shed musty? Physical motion away from the past (symbolized by the shed), towards the future (the path towards home), symbolizes the movement in the story from past to the future. We are done with history. It is in the musty past.
162 TEACHING - Observations - Is Adam now an expert? Adam is now a trained observer. He notices the shape of stones, the color of stones, the types of walls, and the relationship between size, shape, and construction. Square slabby stones build the best walls; rounded stones the worst.
163 ENVIRONMENT - Lichens - What are lichens? Lichens are a symbiotic amalgam of algae and fungi, in which the algae provide the carbohydrates via photosynthesis, whereas the fungi provides the habitat. Some kinds of lichens grow so slowly that they are nearly 10,000 years old. Most of those in New England grow rapidly for several decades, then slow down in their rate of growth, and thus cannot reliably be used to date the stone. When dry, lichens are crunchy like cornflakes.
164 ENVIRONMENT - Habitat - What animals live in stone walls? It is not just humans that love stone walls. They are habitat for many creatures because they provide both protection and a dry place to live. New England would have less habitat diversity without stone walls.
HEADING HOME (Aerial view with geese)
"When they reached the porch, Grampa stopped to look back at the land that he loved. He pulled the letter from his pocket, unfolded it, and held it out to his grandson. "Well, young man," he said. "What's your advice? Should we sell our walls, or not?" Adam had completely forgotten  about the stonemason's letter. His eyes swept the hills and fields, trying to picture them barren of walls , like libraries without books. Earlier that very day, he had answered the same question so easily. If someone wanted to pay good money for a pile of old stones, he had thought, then why not? But now Adam wasnÕt so sure. He couldn't find the right words to reply . He reached out for the letter that Grampa was holding and read it for the very first time. He folded it thoughtfully and pushed it deep into his pocket. "I'm thirsty," said Adam. "Any of that cold cider left in the kitchen?" "Let's go find out," replied Grampa . The old man placed his arm around his grandson's shoulders , and together they went inside. 165 LITERATURE Closure What is the main lesson of the story? We are quite explicit in the point of the story. The history of everything and everybody is connected to the stones, for without them, there would be no earth, and thus, no life. Geologists have a saying that sums this up "no rocks, no ecosystem."
166 LITERATURE - Analogy - How can a stone wall be like a book? Think of the stories that can be told by a single rock; origin, transport, placement, etc. There is a tremendous amount of information in every stone, provided that someone knows how to read it. Like animal tracks, they can be read like books to make a story.
167 LITERATURE - Abruptness - How could Adam forget something so important? The abruptness is necessary here. Questions asked, like "Should we sell our stones?" will not go away. Adam needed the time to experience the stone walls before answering the question.
168 ENVIRONMENT - Visualization - What would it look like without walls? We should never take Nature for granted, even that part of nature created by humans. Sometimes, visualizing the absence of something is the best way to realize what is actually there.
169 TEACHING - Involvement - What do you think Adam should say? Being "not so sure" and not being able to "find the right words to reply..."practically demands that the reader answer the question for themselves. In some situations, selling the stone would be the right thing to do. In others, it would not. Here is a great opportunity for a school writing assignment.
170 TEACHING - Holding back - Does Grampa know if the cider is gone? As before, Adam asks the questions to Grampa, who refuses to bypass the educational opportunity by giving him a straight, factual answer like "yes" or "no." By saying, "Let's go find out" Grampa is involving his grandson in the search for an answer, something that all life-long learners have learned to do.
171 SOCIETY - Physical contact - Does Grampa love his grandson? So much of this book has been about ideas, questions, answers, and decisions. The physical touch of human to human contact is a nice way to end this book. Grampa and grandson are a team now, working across the generations to help protect the environment.
NOTES TO THE ILLUSTRATIONS
FRONTISPIECE (Scattered throughout...) These large, isolated, subrounded boulders are often called glacial erratics. Their corners were knocked off during glacial transport. Their size reflects a transport high in the glacier, usually on the surface, where they could not be crushed into smaller fragments. Some erratics in New England are the size of houses. Title Page - Crows and Cows Walls are built with the "big stones on the bottom, small ones on top." These pastures are "dotted large with cows." Gaps in the walls are evident, where entire sections have collapsed. Some walls "crisscross each other, some are incomplete, and some are being overgrown by the forest.
FARMHOUSE (The old man stood.....) Careful attention to the stones reveal that some are rounded; others slabby in shape. This archetype wall has a top that is not even, nor is it carefully laid. These crude stacks of stone are the most common. Also note the lichens, the small "plant-like" encrustations on the surface of the boulders. A lichen is a symbiotic combination between a fungus (which provides the tissue for support and water retention) and algae (which, by using photosynthesis), provide nutrients for the fungi, in addition to themselves.
BARN AND BICYCLE (A familiar voice...) No notes necessary.
CURIOUS ADAM (The autumn weather...) No notes necessary.
ARMORED MONSTERS ("Look closely," said....) These reconstructions are based on very well preserved fossils from the Devonian Period. The teeth and gills were very primitive by the standards of today's fish. Although rendered plain for artistic purposes, land plants were generally small and quite primitive during the early Paleozoic, a time in earth history when nearly all life took place in the sea. The beach on the shore of the Iapetos Ocean is also emphasized.
SMOKING MOUNTAINS ("Eons passed," he went on .....) This view incorporates much of the rock cycle, in which layers of marine mud and sand (shown accumulating to the lower left ) are converted into the thrusted piles of sedimentary rock that often make up mountains fronting subduction zones, those areas in which one plate subsides beneath another, for example, like those ringing much of the north Pacific Ocean today. Water, the chief weathering agent, is represented in liquid (ocean) solid (snowbanks), and vapor (clouds) phases to illustrate the hydrologic cycle. Interestingly, the existence of volcanoes is largely dependent on water, a compound that, by reducing the melting temperature of lava, allows volcanoes to form near continental margins. The absence of land plants is intentional because they had not yet evolved into forests. Most of earth history took place in the absence of plants.
FROZEN GRAVEL ("I'll show you what I mean," said....) This stream is flowing much more quickly than in the previous scene. Fast water is needed to transport gravel, especially on a low slope. The ocean, as the ultimate resting place of most sand and gravel, is also shown.
FEEL THESE SCRATCHES (Reaching below the silken cobwebs, ...) Note the elongate scratches on the stone that were carved as the rock was dragged along the bed of the glacier.
ICE AGE (Grampa paused, transported.....) Ice is fractured, blue, cavernous, layered, cold. Its meltwater is torrential. The land is "bleak and bare and brown." Its brown dust is swirled up by the "gusty winds" which are so typical of periglacial areas. Boulders litter the areas that would one day be farm fields. The bedrock, or ledge, in the lower right is scratched by the passage of the glacier.
TUNDRA LIFE (Grampa cleared his throat....) From left to right across this, as well as the preceding page, this scene shows the slow succession from full glacial conditions to the bleakness of recently deglaciated terrain, to the tundra, then finally to the first coniferous forests. Caribou and mammoths are signature tundra animals, and were widely present in the northeastern North America prior to the arrival of the deciduous forest, between 9000 and 8000 years ago.
WALKING THE WALL (Wordlessly, the two....) A fire-reddened, cracked rock, part of an Indian campfire, could easily end up in a stone wall.
FOSSIL CAMPFIRE (But what about the campfire? When ....) This scene is full of "hidden" pictures. Find the spruce trees, like those on the preceding page. Note the children playing. The child hiding. The broken pots. Some of the faces resemble those of Grampa and Adam.
TAKING THE FOREST (The ancestors of Adam's....) The "bonfires that glowed orange and red through long days and nights" resemble the volcanoes from previous scenes, suggesting that humans and nature are both manifestations of the same force. The treeline against the sky is very different; here the deciduous skyline has replaced the coniferous one. The original fields are littered with stumps, instead of stone, although just a few seem to be poking up. There are no stone walls. It is too early in the process of transformation. The darkness of the smoke suggests a vegetable genocide, a major transformation from forest to farm.
GRAMPA'S TRICK (Grandfather and grandson...) No notes necessary.
FROM OUTER SPACE (Stones, like those the...) This meteorite is much larger than would normally be expected. Its rough outer shape is typical of differentially ablated meteorites. It looks like furnace slag, and for the same reasons.
CREATION (Grampa leaned back...) The moon, at top center, shows some of the craters and mares (lava seas) that have resulted from large impacts by asteroids or comets. The same thing happens on earth, but the scars are healed by weathering and tectonic forces. The east coast of the United States is shown. Clouds, circling a low-pressure cell, create a bulls-eye pattern with New England at the center. A shooting star, complete with a smiling elderly face carved from mountains and transporting a baby to earth, is heading straight for the family farm. A shock wave precedes the massive object that will land on a glacier, then be transported to the farm, where it will be discovered by Adam.
PICKING FIELDSTONE (From a distance, Adam called....) These are tillage fields which must be kept clear of stone, otherwise the horse-drawn implements would be broken. A stone boat, complete with a whiffletree (a contraption made of wood and chain that helps even out the pull from several horses), is loaded with stone, destined to be tossed to the wall.
ADAM'S KNOWING LOOK (They left the musty shed ....) Adam invites you to see what lies beneath the rock. Beneath it is an understanding of the "circle of life" flowing from rocks to plants to the atmosphere.
HEADING HOME (When they reached the porch....) No notes necessary.