Abandoned stone walls are the signatures of rural New England. Crisscrossing the parks, suburbs, and farms of nearly every village and town, they are relics of a vanished agricultural civilization that once flourished in hillside farming communities. In 1939, the mining engineer Oliver Bowles, using data from an 1872 Department of Agriculture report on fences, estimated that there were approximately 240,000 miles of stone walls in New England.1 That's longer than the U.S. coastline, or even the distance to the Moon at perigee. The mass of stone used in those walls is greater than that from all the remaining ancient monuments put together.
There are old stone walls elsewhere, but only in New England do they rise above the level of architectural ornaments to the status of landforms. Kentucky has its caves, Florida its coral reefs, Louisiana its bayous, Arizona its arroyos, Washington its volcanoes, Minnesota its lakes, and New England its stone walls. The landscape would simply not be the same without them.
Conventional histories correctly describe how New England's stone walls were built by farmers who patiently cleared glacier-dropped stones from their fields. But his tory alone cannot account for the magnitude of the phenomenon, or for their structure—thick, low, and crudely stacked. To understand the archetypal stone walls in New England—primitive, mortar-free, and "tossed" rather than carefully laid—one must turn to the techniques of the natural sciences, in which observation, induction, and analysis carry more weight than the quasimythic tales of early America.
The story of stone walls is a very old one, and is appropriately told by a geologist, whose job it is to reconstruct the history of the Earth. The emergence and decay of New England's stone walls falls under the domain of geoarchaeology, a subdiscipline whose goal is to interpret human artifacts within a broader geological perspective. Consider this book a geoarchaeological study of stone walls, the first of its kind.
Stone walls lie at the intersection of science and history, which became woven together during the transformation of wilderness into family farms, and have been part of the same fabric ever since. Although the New England upland has many old, dilapidated walls, stones were not always abundant in the region.
The raw material from which the stones were made began as mud from oceans, here and there, that have long since vanished. For example, much of central New England once lay in a narrowing sea that disappeared completely when North America, Africa, and Europe merged as part of a supercontinent called Pangaea. Just before the continents separated, this material was deeply buried, squeezed, and sheared into a beautifully swirled lump of hot rock. Over time, it cooled, hardened, decompressed, and rose up to become hard bedrock, mantled by deep, clay-rich, pinkish-yellow, less fertile soils, and covered mostly by forest.
New England did not become stony until the Lauren-tide Ice Sheet invaded the region from central Canada fifteen to thirty thousand years ago. It stripped away the last of these ancient soils, scouring the land down to its bedrock, lifting up billions of stone slabs and scattering them across the region. It also left behind "till," a hardpan soil that was, almost single-handedly, responsible for the success of the grazing economy in New England, which provided its beef, bacon, and butter. As the lush, temperate, deciduous forest returned, however, natural processes within the soil buried most of the stones beneath the thick, organic, loamy soil that was so often discovered by pioneering settlers. The stones were there, but most were hidden from sight.
Native American tribes—Iroquois, Mohegan, Pequot, Penobscot, Nipmuck and Wampanoag, and others, as well as their ancestors—became an important part of the forest ecosystem throughout northeastern North America during the epoch after deglaciation. They settled intensively in the coastal lowlands and large river valleys and, during the last thousand years, cultivated crops. But their resident populations remained negligible on the upland terrain, where, to the south, old-growth forests of maple, oak, hemlock, hickory, and pine flourished, and to the north, birch, maple, spruce, and beech, in spite of frequent disturbance by wind storms and fire. Native hunting parties trod lightly on the forest floor, leaving the stones untouched and the soils thickening quietly and ceaselessly. This was not the case on the other side of the Atlantic, where the Neolithic ancestors of the English had been tilling and grazing upland soils for millennia.
New England upland soils continued to thicken during early European settlement of the region, which began with the arrival of the Pilgrims at Plymouth, Massachusetts, in 1620. Agricultural fields of the original colonies and "plantations" were generally located in stone-free coastal lowlands and in broad river valleys. These settlements were initially somewhat communal; farmers shared common pastures and tillage fields during the day, and retreated to the protection of densely occupied villages at night. Private property did exist, but it lay within larger, community-managed parcels on floodplains. The upland remained a dangerous, largely unoccupied place to the settlers until lingering hostilities between the colonists and the Native Americans lessened with the end of the French and Indian Wars in the mid-eighteenth century. It was during this phase that early stone walls were constructed, usually near villages and often with stone taken from quarries and slopes rather than from fields; meanwhile, the stones of the interior remained hidden beneath the old-growth forests and a deepening, rich soil.
But during the last half century before the American Revolution, thousands of freedom-seeking sons and daughters—formerly confined in increasingly crowded ancestral villages like Boston, Hartford, Providence, New Haven, and Portland (once called Falmouth)—began to establish pioneering settlements in the thickly wooded interior. By that time land-use practices had already shifted to a more broadly distributed pattern of independent, self-sufficient, freehold-ing farmers. The ideological transition toward individual liberty and private property spread a patchwork of private farms over the rich soils of the uplands, each of which required well-defined boundaries and plenty of fencing.
The rapid spread of farms across the uplands coincided with the culminating century of the "Little Ice Age," a climatic epoch that had begun about A.D. 1300 and ended in the late nineteenth century. This marked the beginning of the present phase of climatic warming; colonial times were colder times. As pioneers cleared the forests, there was initially plenty of wood for heating and fencing, and there were not that many stones, except in the worst places. But soon after deforestation, especially on tillage land, the soil became much more exposed to winter cold, causing it to freeze deeply before each inevitable spring thaw. The deep freezing greatly accelerated the process of frost heaving, in which stones are incrementally lifted through the finer-grained soil, toward the surface. When spring rains and snowmelt came, the water couldn't infiltrate as easily as through unfrozen, forested soil, forcing it to flow over the surface with erosive force, removing the loam and concentrating the stone. The clearing of stones from pastures and fields became an annual chore for at least a generation.
In colonial and early America, farmers used their fences to pen animals for the strategic dropping of manure and to separate livestock and crops. Subdivision of land within families added even more boundaries. Thousands of fence lines became magnets for the stone refuse that would otherwise have ended up in piles. Stones were often lugged to field side by hand and tossed one upon the other. More commonly, a load of stone was skidded to the edge of the field on a stout wooden sled pulled by a team of oxen. The large boulders were rolled into position; smaller stones were tossed above and between them. As the stone accumulated, primitive "tossed" walls began to rise up out of the weeds, replacing the lower tiers of wooden fences.
During the early decades of the eighteenth century, many primitive walls were rebuilt into more architecturally pleasing forms, especially on prosperous farms and estates. This era of agricultural improvement coincided with a time when farm populations were rising and when a surplus of labor was available. It also coincided with a time when the stone supply was increasing relative to the wood supply. With cash, labor, and a copious supply of stone already in place, hundreds of thousands of walls were built and rebuilt throughout the region by farmers, hired labor, the Linemployed, and slaves.
The authentic early stone walls of New England served many purposes. A small few were tall enough and strong enough to qualify as legal fences. Many others were expedient boundary markers separating private lands, No Trespassing signs written in stone. A few were ornaments, built for aesthetic purposes or to display wealth. But almost every wall also served a more fundamental, arguably higher purpose: to hold the waste stone that once littered farm fields. However tidy well-built walls might appear, most functioned originally as linear landfills, built to hold nonbiodegradable agricultural refuse.
Nearly every attribute of authentic backwoods walls is consistent with this claim. For example, the size of an enclosed field was often determined by the number of walls required to hold the stone that was picked up from it. The height of most walls—thigh high—was governed more by the ergonomics of lifting and tossing stone than by the mandate of fencing. The simple, inward-slanting, internal structure of most walls was a "least-work" trade-off between the investment of energy required to build the wall and its long-term stability.
Stone walls not only transformed waste into something useful, they arguably "improved" the local wildlife habitat with respect to diversity. Prior to wall construction, the dry-land habitats of cliffs and ledges were much more restricted in New England; animals and plants that had adapted to such terrain now had a greater chance to survive because stone walls and stone ledges offered similar opportunities.
Walls have also influenced the terrain directly. Hilltop walls forced the rain toward different streams. Lowland walls impounded many small wetlands, caused the buildup of soil on slopes, and acted as underground drains on floodplains. Stone walls are so tightly enmeshed with streams, slopes, and soils that the distinction between wall and nonwall is often unclear.
Paying closer attention to stone walls from a scientific perspective helps deconstruct some pervasive historic myths. First is the notion that New England pioneers cleared a rocky wasteland in order to create their farms. In reality, upland New England farms were then, and remained at all times provided they were treated with care, largely fertile until they were abandoned for cultural and technological reasons. Most of the stone that found its way into walls was a delayed and inadvertent consequence of deforestation. Like the local extinction of bears, wolves, and cougars, stony soils were an unavoidable environmental consequence of wilderness conversion.
Second, there is the mistaken impression that stone walls are primarily a colonial phenomenon. They are not. Although walls were being built from the time of the first settlement to the end of the pioneering stage, most were built in the half century between the end of the American Revolution and the construction of the first railroads. Early colonial settlements were in river and coastal lowlands, which were usually underlain by thick deposits of glacial sand and mud devoid of stone except on rocky headlands. There are indeed many colonial-era stone walls in the ancient towns of Rhode Island, eastern Massachusetts, and southern Connecticut. But even in those regions, most old walls were built later.
Finally, most stone walls were never stand-alone fences, intentionally built to separate livestock and crops or one neighbor from another. Nearly all needed some help from wood, then later wire, to accomplish this task. Fences created the walls, rather than the other way around.
Knowing more about stone walls allows one to appreciate them—and the landscape they embellish—more keenly. With very little effort, you can also become a more discriminating admirer of stone walls. Initially, you will see walls where you might not have noticed them before. Later, you will see more conspicuous differences among walls and stones. Finally, you will discern subtle clues to a wall's construction and its history, both natural and human.
To know New England well, one must know its stone walls. Forged at scorching temperatures deep within the Earth and brought to the region by huge glaciers, each stone is the result of both fire and ice. Today's stone walls continue to be transformed, largely by biological processes. Bacteria tarnish them. Lichens dissolve them. Vines penetrate and loosen their stones. Trees, blown down during hurricanes, knock large gaps in walls, as though taking bites of the earth. Left untended, every wall will come apart, tumble to the ground, disperse over acres of soil, and be buried by the encroaching vegetation. Although inanimate, stone walls have an important story to tell. They give us a clock by which we can judge the passage of almost unimaginable time.