Does this chamber constitute pre-European contact? Or was it built in the 19th century as a place for a teenage tryst? Or something else? How can we investigate which is true? (Note: This photo was sent to me a long time ago by a forgotten helper who I hope will contact me again so I can properly credit them.)

We think we know more about stone walls than we actually do. It’s surprising how little data-based science there is about stone walls across a variety of scales.  This statement includes my three books as well, none of which were based on hypothesis-driven, site-specific investigations. For example, consider these questions:

  1. How much stone wall is there in New England?
  2. Do walls come in different types?
  3. Is there such a thing as an average wall?
  4. What organisims use them as habitat?
  5. Are there pre-European stone walls in New England?


M Life WallStreamHabitat
Walls have created habitat. In this case, what had been a continuous stream became a wetland behind the collapsed wall and a cascade through it, giving two new habitats.

Questions like these can presently be answered only by sweeping generalizations, crude estimates, or anecdotal, case-by-case scenarios.  And now the answers, number for number.

  1. We really don’t know how much wall there is, because the only good census was taken in 1871, this was anecdotal, and many of those walls have been destroyed since.  However, we are likely to have a good estimate within a decade, thanks to the combination of GIS and LiDar mapping.
  2. Yes, walls come in many distinct types.  The classification in progress is provisional, and has yet to be tested and improved by teams of field scientists.
  3.  An average wall?  Not really. There is no such thing as an average wall.  As with the “average animal,” the phenomenon is too broad to yield a meaningful average. We must first classify walls into taxa, and then averages become very meaningful.
  4. We have anecdotal reports, for example chipmunks and garter snakes.  But census-based research is generally lacking.
  5. There must be, based on the working definition we’re using.  Ad hoc expedient walls would have made excellent hunting blinds and expedient enclosures to provide protection against the elements. The problem is we haven’t yet dated them. Cosmogenic exposure age dating methods, for example 10Be, and 26Al may help.


Investigation is the most under-served of the four major goals of the SWI.  Having made more progress on other fronts, the time has come to do more scientific research on the phenomenon.  If you have something to add, don’t hesitate to contact the SWI.  For in-progress investigations, link to:

Map pattern of walls on historic photo from Block Island. Source: my photograph of an anonymous historic photograph taken in the 1880s and copyrighted by Robert Downie.