Author: Thorson Robert

Petroleum Walls and Enormous Boulders

Screenshot of 44-second video by Sam Wadsworth from late December, 2023. It shows oversized stones pushed and set on a wall in Monterey, Massachusetts. This large, glacially milled boulder rests above a classic mix of sharp-edged (slabs) and round-edged slabs (pillows). The diagonal line from upper left to lower right is a recent and sharply broken edge, with the upper side having a rounded (milled) surface with a moss-lichen-patina and the lower side having  jagged fresh rock on which may be vertical scrape marks running against the grain (metamorphic foliation).  Because the boulder rests on stones that are continuous across the gap in the wall, I interpret that the boulder was moved, broken, and scraped in the recent past by a large machine fueled by petroleum.

During the dark days of  December a curious character from Monterey, Massachusetts named Sam Wadsworth contacted me from the heart of the Berkshires.  Having read my book Stone by Stone, he reached out to ask me two two excellent questions that I decided to answer in this post as a surprise, rather than an email.   He asks: What is “the maximum size/weight of boulder that could be moved by man and oxen”? He also asks:  Did the farmers who cleared the land “arrange stone walls to include such giant stones or did they move them”?

Though both questions are straightforward, neither has a good answer that I know of.

The second question is easier, so I’ll take it on first.  It concerns enormous boulders ranging in size from kitchen tables to snow-plow trucks that have a wall of smaller stones heading outward in various directions. The wall extensions are usually straight, especially if the walls are massive, but lower, less massive walls are usually more irregular, occasionally sinusoidal at the scale of yards.  I have also seen straight, well-built walls cut right across and incorporate large, apparently un-moved stones that must have lain directly in the way of the line.

Such enormous stones were were almost certainly never moved because it would take a huge amount of unnecessary effort and ingenuity to move them,  because they do not exhibit the breakage, scraping, or crushing marks that would be expected by movement, and because boulders  enveloped by walls are crossed at random positions.  Had the been moved, the stones would have been turned into alignment.   The default hypothesis is all such large stones, with or without wall attachments, are in situ glacial erratics that have never been moved.  In my four-part particle size nomenclature, they are residual stones that were left in place, rather than moved: (1) with some sort of assistance (assisted, meaning livestock, machines, levers, ramps, etc), (2) hefted with human hands (manually moved by one or two people), or; (3) handled with one hand (one-hander).

The combination of large residual stones attached to segments of walls gives rise to the appearance of tadpoles or bolts with the large head being the boulder and the long part being the segment of wall with smaller stones.  Within the CSL (Ceremonial Stone Landscape) community, some of these features are interpreted as serpent effigies with boulders for heads and walls for bodies, especially if the bodies are sinusoidal.  Some may indeed be just that. But, then again, they might not be.

Sam’s first question of how large a stone can be moved by a man and oxen is probably unanswerable because it’s only a matter of determination, ingenuity, and the number of oxen added to the team.  The Greek mathematician Archimedes (287-212 BCE) one wrote: “Give me a lever long enough and a fulcrum on which to place it, and I shall move the world.” Anecdotally, I don’t think I’ve seen an oxen-moved stone in a wall larger than 3 feet square, or about a ton in weight. Larger ones occur in cut-stone project like bridges and monuments.

With the question about residual boulders out of the way, and the one about maximum size unresolved, I asked Sam:  “Why not have another look for clues to the timing and character of movement? And, while you’re at it, measure the largest stones you know that were moved.”

He did just that, converting his curiosity into a holiday outing for his two daughters and a 60-pond dog.  By January 2, 2024, he had sent me a full report by email.  He found no obvious marks on the stones that might have been clues.  Of the five large boulders he measured from the wall, the largest had a circumference of 26 feet.  Assuming a spherical shape and “using standard formulae for arriving at volumes and a Google value of 175 pounds per cubic foot for granite,” the largest boulder would have weighed 52,000 pounds or about 25 tons. [A 26 foot circumference yields a radius of 4.1 feet, which yields a volume of 296.6 cubic feet, which yields a weight of 51,914 pounds.]  This, boulder is the broken one that ends his video below, and which I share with his permission.  My calculated weight is easily within the range of the what a large bulldozer can push, especially if the object is round enough to roll.

But when was it moved?  Based on the limited lichen cover of some of the displaced stone, I suggest less than a century.  Sam confirmed this by measuring the diameter of a sample of ten trees in the area from which the stones were moved. Using standard guess-timates, the forest was only about 50 years old.

In conclusion, I interpret that his walls are petroleum walls.  This is the term I’ve used for years to describe hybrid walls that are common throughout New England.  Those with oversized boulders either pushed in a row against an older wall or set on top of an older wall.    This makes sense given the local land use history.  A time of farming limited to livestock power creates the original wall.  And a subsequent time of forestry associated with big yellow machines capable of moving enormous stones, and caring less about how the walls end up looking.

Sam got his answer the hard way: by scratching his head, doing his homework, asking for ideas, sending his report to me, and editing the results.   The good news is that his hard way was also the fun way.  The getting out there to explore history by being a stone wall detective. And the corresponding back and forth about a mutual joy.


Below is my commentary on the 44 second video by Sam Wadsworth. The terminology follows my book Exploring Stone Walls (NYC: Bloomsbury, 2005) and, more recently, Taxonomy and Nomenclature of the Stone Domain in New England. The digital time is in minutes and seconds.

0.01                 The boulder in the foreground is adjacent to the pre-existing wall, possibly (but not likely) having rolled off it. It also has a sharply broken edge.  The rounded boulder in the background rests atop a massive tablet, which, in turn, rests above the lower wall. The sequence is clear: wall, then tablet, then rounded boulder.

0:10-0.19          The view with the dog initially to the left shows the pre-existing wall quite clearly as a tier of assisted sized stones, surmounted by a tier of hefted- and one-hander-sized stones placed above them and tucked into void spaces.  This appears to be a normal single wall in my taxonomy.

Within this segment, at 0.15, is an spur, or out-dent of the wall consisting of a few stones directly below the large tablet. Circumstantially, it appears that these were knocked down when the tablet, or the superimposed heavier boulder, were put in place. The freshness of the joint face on the central stone in the spur suggests it was recently displaced.

0.25                 The large boulder seems to rest on crushed rock residue different from the built wall on either side.  This is a mystery because simply placing the boulder would not crush the stone like this. Where did the crushed rock come from?

0.30                 We’re back to the original wall, a single-tiered segment, likely a normal double wall, built with care, with a laid degree of order,and  with visible courses, the largest stones being at the top.

0.35                 Four large stones, two slabs and two massive boulders are placed on and over the wall, suggesting it’s built to clear stone from the near side.

0.44                 The largest stone is clearly placed in a gap on a built wall, with the flat side down. Other large stones are placed on and slightly over the wall, indicating construction, likely by a front-end loader, from the near side.


Smithsonian Essay

Autum stone walls New England
Opening photo for Smithsonian’s  Nov 14, essay titled “How Stone Walls Became a Signature Landform of New England,” written by Robert Thorson. Photo credit to Ken Canning, Getty Images.

On November 14th, 2023, Smithsonian published an essay that has been slowly coming together for several years.  “How Stone Walls Became a Signature Landform of New England” is bringing national attention to a regional phenomenon. It’s also bringing readers from literature, history, and science to the same proverbial page.

This essay is written in a style known as long-form journalism, in this case having nearly 3000 carefully chosen words and five stunning stock photos.  In this genre, the writing moves back and forth between my own travels, Robert Frost’s poetry, facts about stone walls, New England history, and environmental issues, including climate change.

For readers lacking the patience to read such a long essay, or for those wanting help zooming in on something specific,  I decided to write a “Cliffs Notes” version of the essay that extracts and abstracts its key ideas in the order in which they appear. All of these ideas are more fully explained in the text and supporting links. Consider them “talking points” for the larger cultural conversation we’re having about the appreciation, conservation, and investigation of stone walls, and how all this can be used to educate the rising generation of movers and shakers.  For teachers, I hope that my pithy statements can be tweaked into learning objectives that could be taught outdoors in front of an old stone wall.

POETIC  ICONS.  Robert Frost’s poetry was perfectly timed to kick-start New England’s appreciation of stone walls, making them as valuable as cultural icons as they ever were as utilitarian fences.  His meditations on them at his farm in Derry, NH became the core of all his writing.

GOOD FENCES?   The building of barriers between human communities has always been a mixed blessing — a tradeoff between our evolved  needs for territorial markers and for social openness.  Do we need a clear line between us and them?

DETERMINISM.  Statistically, New England’s walls are far more alike than they are different, given the deterministic forcings associated with the landscape history of bedrock creation, glacial action, the agricultural makeover, and subsequent reforestation.  Natural, rather than cultural, factors account for most of the variation we see.

ORDER TO DISORDER.   Absent human care, all walls are fated to disappear from the landscape because they are ordered structures in a world that naturally trends toward disorder.  From low-entropy to high-entropy.  Nature ‘wants them down” via chemical and physical weathering, the growing and falling of trees, the heaving of the ground by frost, and many other factors including seismic shaking.  Nature also wants the stones more widely and randomly dispersed over the area of adjacent land and the volume of the soil.

CLIMATE CHANGE.  New England, stone walls will likely fall apart faster in the warmer, wetter climate of modernity and future projections.

LITERARY LICENSE.   Frost’s “Mending Wall,” the most famous stone wall in the U.S., is a poetic conflation of two actual walls on opposite sides of the parcel of land behind the barn at Frost’s Farm.  The better-built stack of slabs to the west that requires little maintenance, and  the tumbling row of cobbles and boulders to the east that requires constant maintenance.

HISTORIC TRANSITION.  The early 20th century was a time of landscape transition, from smaller agricultural communities to larger industrial ones, from dirt to bituminous roads, from horses and oxen to automobiles and tractors, and from open to reforested parcels. Robert Frost capitalized on the cusp of change. 

BINDING THREADS.  As a consequence of the early 20th century transition, the walls originally built to divide agricultural properties became the binding threads of a new cultural identity emphasizing the region’s shared agrarian heritage. 

SIGNATURE LANDFORM.  Though nearly ubiquitous in New England, stone walls are only locally present elsewhere in the US owing to the requirement that three limiting factors be present: hard crystalline rock like granite and gneiss; glacial till subsoils; and a family farms in need of dense fencing.

MAPPING.  New techniques involving LIDAR (Light Ranging and Detection), GIS (Geographic Information Systems) and AI (Artificial Intelligence) are accelerating progress in the mapping of New England’s estimated 240,000 miles of stone wall in New England. 

STRIP MINING.  The greater power of fossil fuels in the Anthropocene epoch has led to widespread destruction of many historic walls in New England for the purposes of commercial agriculture and for the strip-mining of stone for road sub-grade and suburban architecture.  

HABITAT:  The loss of stone walls is also the  loss of a unique habitat, and therefore a loss of biodiversity.  Ecologically, the “drylands” of stone walls are analogous to the “wetlands” of nearby floodplains, swamps, marshes, fens, and bogs.  And their ecological effects extend beyond the lines of stone.

CONSERVATION:  Ever so gradually, we are seeing a rise in legal frameworks and administrative policies devoted to the conservation and management of stone walls.  The trend toward appreciation, protection, and education is gaining ground.








Bobcat Habitat

Bobcat on wall, infrared
Bobcat with glowing eyes on wall in Lee New Hampshire. Still image from 20-second infrared video taken June 21, 2023 with a GardePro wildlife camera. Courtesy of Jeff Hoy.

New England residents and visitors love the region’s historic stone walls. They also love the the fact that this region’s now thickly wooded landscape is being re-wilded by creatures like bobcats.  These formerly widespread natural predators were locally exterminated because they were a threat to livestock, and those that remained avoided the open landscape of fields and pastures on former farms. But now bobcats are coming back, and stone walls seem to be a part of that story.

Over the years I’ve frequently described the ecological importance of stone walls, based on my own eyewitness accounts of chipmunks, squirrels, feral cats, foxes, human children, turkeys, snakes, and many more. But never have I seen a more dramatic visual proof of the link between animals and walls  than the 20-second video below. It shows a bobcat (Lynx rufus) using a low, bouldery stone wall first as a hunting blind and later as an elevated corridor along which it walked while scanning for prey.


This video was obtained and provided by Jeff Hoy.  The setting is Lee New Hampshire, a thickly wooded residential town in southern New Hampshire west of Durham. His tree-mounted, infrared wildlife camera, a GardePro, was tripped by motion at dusk on the cool, quiet, and clear solstice night of June 21, 2023.  The time was 8:35 PM.  The temperature was 59 degrees Fahrenheit (15 degrees C).  The ambient background noise was quiet except for distant traffic and the tweets of birds.

At zero seconds, the camera shows the stone-sized head of Lynx rufus moving side to side as it peered over a gap in the wall. From zero to three seconds the bobcat continued to use the wall as a low hunting blind. From three to ten seconds, it comes out of hiding and crosses the wall in order to climb to its crest.  From ten to twenty seconds it stealthily walks the wall as a transportation corridor, looking (and presumably listening) in all directions.

I found a good description of bobcat behavior and ecology provided by the Massachusetts Division of Fisheries and Wildlife.  The bobcat photo they chose (reproduced below), shows one standing next to a stone wall.  This pairing is probably no accident. I suspect that walls and bobcats go together because cats are proficient climbers that need to travel miles per day in search of prey. Walls provide an elevated and stable corridor along which the cats can move while hunting with their acute senses of sight and hearing.  Additionally, walls are common habitats for the cat’s principle prey, which are mid-sized to small mammals.    By providing both habitat for their prey and features that enhance predatory behaviors, stone walls are probably greatly appreciated by bobcats.

Bobcat in front of stone wall.
Uncredited photo of bobcat standing in front of a stone wall. From the website of the Mass Div. Fisheries and Wildlife.

Moving beyond the specifics of bobcats, the stone walls of New England diversify the entire landscape, being an elevated lattice-work of stony drylands in an otherwise moist world. They are similar in composition to the rubble of rock ledges, but they are very different from ledges in being much more ubiquitous, extensive, and linked to one another.  With respect to animal behavior, they are barriers separating different habitats, corridors that guide movement, habitats for those living within the pore spaces of walls, and sites for burrows beneath their basal stones.  Each partitions the world into two realms: sunny and shaded, uphill and downhill, windward and leeward, and sites of thicker and thinner soils.

If stone walls diversify and enhance the habitat for bobcats, is the same enhancement true for other species?  For plants?  For our wildlands?



Stone Wall Science & Management

Imminently, the journal Historical Archaeology will be publishing my mini-monograph “Taxonomy and Nomenclature of the Stone Domain in New England” as an oversized journal article in what they describe as “the leading journal in the study of the archaeology of the modern era,” and “the scholarly journal of the “Society for Historical Archaeology.” Being a geologist, I have no basis for quibbling with those statements. And, as an outsider to the field, I especially pleased that they will publish my “new tool” after careful peer review of a manuscript submitted  in March 2022, accepted in October 2022, and copy-edited last winter.  With permission, I share its abstract.

The Euro-settlement of rural New England created an agro-ecosystem of fenced fields and pastures linked to human settlements and hydro-powered village industry. The most salient archaeological result was the stone domain, a massive, sprawling constellation of stone features surviving  as mainly undocumented ruins within reforested, closed-canopy woodlands.  We present a rigorous taxonomy for this stone domain  based on objective field criteria that is rendered user-friendly by incorporating vernacular typologies and functional interpretations.  The domain’s most salient class of features are stone walls, here defined as objects meeting five inclusive criteria: material, granularity, elongation, continuity, and height. We also offer a suggested nomenclature and descriptive protocol for archaeological field documentation of wall stones (size, shape, arrangement, lithology) and wall structures (courses, lines, tiers, segments, contacts, terminations, and junctions). Our methodological tools complement recent computationally intensive mapping tools of LiDAR, drone-imaging, and machine learning.

Note that I am not publishing any archaeological interpretations. Rather, I’m providing what one reviewer deemed similar to a “Munsell Soil Color Book,” an objective tool for naming and classifying that will help steer the study of relict stone walls toward science, in this case historical archaeology, which, for the Anthropocene, is also surface-process geology.  Though there was some back and forth during revision, my assertion that walls are artifacts, rather than features, survived the chopping block.  My hope is that better science will lead to better archaeology, which will lead to better environmental management. In fact, the parallels between wetland conservation and dryland (stone walls) conservation are intriguing.

This project has been a long time coming. In 2005, a preliminary taxonomy was published in my book Exploring Stone Walls, which the publisher Bloomsbury let go out of print. In 2009, I put a revised version up on this website.  Since then, I’ve been tweaking the taxonomy and naming protocols while consulting with colleagues that included three state archaeologists.  My plan was to hold off publishing in a technical journal until I felt like I had things right. That feeling never came, so I decided to take a deep breath and move forward, warts and all.

With a classification system in place, I then moved on to stone wall management and conservation,  putting together a draft set of considerations and suggestions for any organizations interested in writing more science-based regulations for protecting this precious resource.





“Stone By Stone” Becomes Audiobook

September 2002 saw the publication of Stone By Stone: The Magnificent History in New England’s Stone Walls.  Within a week it became a steady New England bestseller. Within the year it went through several hardcover printings and earned the 2003 Connecticut Book Award for nonfiction. By 2004, it was released in paperback.  Originally published by Walker & Company, a new edition was published by Bloomsbury.  The book continues to sell off the backlist.

Throughout it all, there was no audiobook.  This changed in summer 2022 when Tantor Audio, a subsidiary of Recorded Books since 2015, saw an opportunity to publish  this “classic” as an audiobook, doing so on October 25, 2022.  I had the opportunity to read the script.

For those of you who are interested, ask your library to order the audiobook or simply purchase it from Tantor Audio.

Stone Shelters in the Sierras and New England

Shelter in Sierras
Stone Shelter in White Mountains, CA, USA in the glacial high Sierras. Elizabeth Wing.

Years ago, I was traveling through the small town of Putre in northern Chile, when I saw something astonishing.  The shape, size, and composition of its ancient stone walls in the high Andes at an elevation of 3500 meters (11,060 feet) were remarkably similar to those I’d seen in the lowland hills of interior New England. Though the inhabitants of pre-Columbian South America were raising camelids rather than sheep and cows, and though they were worlds apart from post-Columbian North American Yankees, their primitive farmstead stonework was remarkably similar.  Why?  Because the same three fundamental factors came together in time and space: the need to enclose grazing animals in heavily glaciated terrain underlain by crystalline igneous and(or) high-grade metamorphic rock.

Similarly, The Distinctively Basque Stone Shelters of California’s White Mountains, are remarkably similar to some I’ve seen in New England because the same three factors were controlling the outcome: animal enclosure, glaciated terrain, and hard crystalline rock.  This new, 2022, article by Michael R. Wing, Elizabeth H. Wing, and Amin M. Al-Jamal, describes the shelters built during the mid 19th century to protect sheep grazing in the high meadows of the White Mountains of high eastern Sierras of California. The phrase “distinctly Basque” refers not to a cultural style of construction, but to the certain historic knowledge that they were built by Basque (or adjacent French) herders.

The captioned illustration above reproduces their Figure 1, a photo of Big Stone Shelter, which located above tree line at an elevation of 3840 meters (12,600 feet), even higher than in Putre, Chile.  Its features –a glacially rounded boulder, a mix of angular and milled stones, the overall form, and the pattern of stacking– are identical to those of primitive fieldstone walls in New England.  And though this shelter is a small enclosure rather than a wall around a land parcel, New England has many such small enclosures in its formerly de-forested highlands, or as niches attached to walls.  Whether some or all of these were roofed with organic material that has since decomposed is unknown.

The similarities in expedient stone construction built by indigenous inhabitants in the high Andes, Basque herders in California Sierras, and farmers in New England demonstrate the adage that form follows function, regardless of historic or cultural setting. Such walls are ecofacts as much as they are artifacts.

Of course, the story of stone structures everywhere is much more complex than the simple connections made above. And these three connections are only a few among many.  But the conclusion is always the same. Beneath cultural overlays, the expedient architectural requirements of herding animals in rocky glaciated landscapes produces similar results.


Landscapes within Walls within Frames

Last spring I had the pleasure of meeting Gary Perdue, a retired producer/director for Public Television who took up photography as a serious hobby, and the stone walls of Rhode Island as his subject.

After years of shooting, he designed an exhibit in which he arranged his photographs as if they were stones in a wall, and then framed that arrangement as if in the profile view of stone wall.  The frame shown in the image above is one of a dozen or more that, taken collectively, create a powerful exhibit.  I had a chance to see it when he drove it to Storrs, CT from State College, PA in a U-Haul van, accompanied by his wife and son.

Gary is seeking additional venues for the exhibit.  If interested, please contact the SWI coordinator Robert M. Thorson  via the Stone Wall Initiative.


“Living on Earth” features Stone Walls

“Many of New England’s stone walls, like this one in New Hampshire, are going back to nature as they fall into disrepair and become overgrown with moss. (Photo: mwms1916, Flickr CC BY-NC-ND 2.0)” [Photo and caption from Living on Earth.]

Living on Earth, hosted by Steve Curwood, is Public Radio International’s weekly Environmental News Magazine. On November 30, 2018, it aired three long segments: Trump Climate Change Report, featuring John Holdren, Obama’s former science advisor; Saving the Sumatran Rhino, featuring freelance journalist Jeremy Hance, and New England’s Stone Walls, featuring Steve Curwood and I examining an abandoned 1755 farmstead in New Hampshire.  The highlight of that 10-minute podcast is the recorded voice of Robert Frost reading his poem Mending Wall. 

Link to Podcast.

Other topics include answers to the questions:  Who built the walls? Why are they special habitats?  Are humans part of their geology? Did wall  help win the American Revolution?

Stone Therapy

Above is a “pile” of well-stacked stone on a boulder somewhere in western New England. This activity would have helped clear a field or pasture. But more importantly, it turned the mundane act of clearing land into a stacking game, leaving cairns and stacks for us to puzzle over and misinterpret as sacred sites.


Yesterday, I learned of a curious case of stonework performed by an elderly man with dementia. The anecdote, published in the Providence Journal for September 2, 1895, refers to a time “60 years ago,” which dates the case to the mid 1830s.  In this case, the stonework was done as “keep-busy” therapy for an aging farmer with dementia, a reason not usually cited as an explanation for odd stone structures found throughout New England.

It is one of the few cases in my experience where the origin of stone structures –walls, piles, enclosures, cairns– is specifically documented in time, place, and purpose.   The lesson here is that odd stone structures need not be expedient or symbolically sacred.  Unless proven otherwise, those dating to before and after European contact might reflect little more than individualistic, idiosyncratic responses to behavioral cues.

Specifically, an “uncle of the owners” living on “the Josiah Dyke place” in northeastern Connecticut, likely East Thompson, had dementia (also known as senility), the condition of losing one’s mind –especially one’s memories– as part of the aging process.  This particular uncle “spent his whole time in the fields, which are full of stones of all sizes, picking up the stones and placing them with great care in heaps” that were “piled up without mortar into pyramids” that “tapered slightly and reached a height of six feet or more.” They were “so well and so solidly built that although built 60 years ago they are still in as good condition as ever, except where mischievous boys have torn them down.”  “The work was so well done that it became a wonder of the countryside,” bringing gawking visitors in “from far and near.”  

The stones remain as a testament to dementia, a condition that plagues millions of adults today, and to the value of stonework in happily passing the time as a form of engagement with the world, even when one’s mind is slip sliding away.   I know this condition from direct experience because my own 96-year old father has it today.  Being a former band conductor, he physically directs the musical memories floating through his mind.  Another resident of his managed care facility knits while she walks, again a response to the urge to do something physical.   Had my father been the farmer’s uncle from 19th century New England, however, he might have felt the urge to stack stone to occupy his mind to pass the time away.

My favorite aspect of this story is that the micro-history of this demented builder faded away in only six decades. Cultural memory and individual memory both fade away, leaving archaeology to fill in the gaps.

NOTE:  This anecdote is based on an excerpt sent to me by Dr. Tim Ives, the Rhode Island state archaeologist. The original is below the line.  Note that the location is given as “northwestern” Connecticut when it is almost certainly “northeastern,” an easy mistake to make by the author.

“This is not the only curiosity of this region, for the whole country in northwestern Connecticut is full of eccentricities of nature and man. On the Josiah Dyke place, in this region, are a number of curious heaps of stones, piled up without mortar into pyramids wThey were placed there over half a century ago by an uncle of the owners of the property. He was demented and spent his whole time in the fields, which are full of stones of all sizes, picking up the stones and placing them with great care in heaps which tapered slightly and reached a height of six feet or more. The work was so well done that it became a wonder of the countryside, and people came from far and near to look at the stone heaps. Now they remain in the fields, visible from the road, although their builder has long since passed away, and few of the farmers in the locality know their history.”

“Getting” the Anthropocene

The Anthropocene is the epoch of geological time we are currently living in, a discrete interval of Earth history during which the collective actions of a  single species —Homo sapiens— is the dominant geological agency operating on our planet. Though the “epoch” is not yet an official “Epoch” (owing to international debate over the date of its lower boundary), there’s no doubt that we’re in the thick of it.   The preceding epoch, the Holocene, contained the bulk of the present interglacial epoch when the human agency was less impactful.  For New England stone walls, the Anthropocene onset dates to 1607, when the first wall was built by the first English colony at Popham Point, Maine.

Work at the University of Connecticut, especially a 2016  article published in the Elsevier journal Anthropocene by Katharine M. Johnson and Will Ouimet, is bringing New England walls to an international audience (Physical properties and spatial controls of stone walls in the northeastern USA: Implications for Anthropocene studies of 17th to early 20th century agriculture,

Philosophically, the key idea for me is that, in the woods of New England, the main Anthropocene impact is already past and was generally positive in diversifying the landscape and leaving archaeological ruins that enhance our lives.