The Revolutionary War, a defining event in American history, dragged along between 1776 and 1783, and its aftermath had an enormous impact on the New England landscape, especially with respect to its stone walls. Most directly, the protracted war drew thousands of young men away from farms, even if only for a few months. Left behind were women, children, the elderly, the infirm, and those unable to leave. Those who remained worked the land even harder in order to help sustain the war effort, provisioning the Continental militias with bacon, beef, cheese, corn, grain, cider, beans, cabbage, squash, and fruit, which was often shipped in the form of brandy.
During the war years, a long-term, future-oriented perspective on land management gave way to a short-term, present-oriented priority for survival. The die had been cast for liberty, and now there was no turning back. The acute effort of winning the war came at the expense of capital improvements, which were often put off. Maintenance was neglected and fences disintegrated. The soils became impoverished as their nutrients were drawn out by crops faster than they were replenished by the addition of manure. Allowing land to rest, or be fallow, was a luxury few farms could afford. Fieldstones accumulated in pastures faster than they could be hauled away.
Rural community life was forever changed by the war. The enormous war debt—which accumulated through lost taxes, higher prices for imported goods, armaments, soldiers' pay, war provisions, and destruction of property—was often paid off in new land rather than in Continental currency, which was hardly worth the paper it was printed on. Also available were large tracts of land abandoned, literally, by the Tories; these were appropriated in various ways, then sold to the sons and daughters of liberty.
After the war, veterans and their war-weary families moved into towns created scarcely a half-century earlier during the initial exodus from colonial coastal villages. During the next two or three decades, the new nation's mood turned optimistic. Birth rates picked up, expanding the population dramatically. Country congregations expanded, overfilling their pews. Parishes split down the middle along largely geographic lines, then, like living cells, divided again and again. This was especially true in the more settled parts of southern and coastal New England.
Prior to its industrialization during the mid-nineteenth century, New England had always been an exceptionally rural population. During the postwar (American Revolution) baby boom, it became an exceptionally young one as well. For example, by the turn of the nineteenth century, only 4 percent of Connecticut residents lived in cities; "every third person was a child younger than five years old; only one person in six was older than 45."1 No matter how many mouths there were to feed, there were twice that number of hands ready to work the land and pick up the stones.
The British naval blockade during the Revolutionary War had cut off the flow of imported manufactured goods, especially metal ones. This precipitated the establishment of Yankee factories in places where hydropower was available, which was on nearly every moderate-size stream. Industries associated with iron manufacturing, shipbuilding, distilling, and packaging accelerated the pace of deforestation, which was already being intensified by the cutting of wood needed to repair war-torn fences and buildings. Progressive industrialization helped concentrate populations in mill villages, creating new local markets for food products. Agricultural prices doubled during the last decade of the eighteenth century, raising the value of rural land throughout settled New England.
Millions of stone walls were built after the beginning of the American Revolution between 1775 and 1825. Several important changes in rural society were responsible for what writer Susan Allport refers to as a "frenzy of wall building." First, the rapid pace of wall construction coincided with the time when the children of the postwar baby boom had grown old enough and strong enough to pick up stones. Surplus labor was also available during one of several postwar recessions. Freed slaves, landless farmers, debtors, groups of "tame" Indians, disabled war veterans, and the generally unemployed were put to work building stone walls. Second, the generally optimistic landowning farmers were self-reliant American citizens with the confidence to build a great nation, if necessary, one stone wall at a time. This epoch also broadly coincided with the Federalist period, a time when farming and animal husbandry became more scientific.
Founded on improvements in public education and greater literacy rates, agricultural societies and journals were established in every state between 1787 and 1794. The secular "bible" of this era was Sam Deane's 1790 dictionary (actually an encyclopedia), whose title speaks for itself: The New England Farmer; or Georgical Dictionary. Containing a Compendious Account of the Ways and Methods in which the Important Art of Husbandry, In all its Various Branches, Is, or may be, Practised, to the Greatest Advantage, In this Country.
But the primary reason for the spread of stone walls on the land during this period was a geological one. Processes operating within and below the soil had combined to produce enough stone so that it could be used to fence the land.
Environmental historians generally conclude that the switch from wood to stone fencing in the early nineteenth century was an economic decision caused by the shortage of wood. For example, David Foster and John O'Keefe, in describing central Massachusetts, near Petersham, assert that, by 1830, "wood was now too valuable to use for fencing, so the abundant stones were used instead." William Cronon provides a more complex view: "The final shift to stone walls was thus a way both of ending the labor cost of repeated fence construction and of conserving disappearing timber resources."
But the switch from wood to stone probably had more to do with the availability of stone than the scarcity of wood as a resource. There is no arguing that, as pioneering plantations evolved into productive farms, the supply of wood shrank steadily, especially that of chestnut and cedar, the most desirable materials for fencing. But it is also true that the supply of stone had been rising steadily. Wood and stone, it seemed, were reciprocal resources. One went up while the other went down. The supply of wood was highest at the outset, before the first tree was cut. Conversely, the supply of stone was highest at the end, when the lands had been cleared the longest.
An 1838 view of the countryside near Groton, Connecticut.
The initial drop in the availability of wood on the landscape was due primarily to forest clearing; whole trees were burned simply to be rid of them. Later losses were driven by the chronic need for heat energy to keep houses and buildings warm, for boiling maple sap, for use in the butchering of animals, and for washing. William Cronon estimated that an average Yankee household used thirty to forty cords of firewood per year, each measuring four feet high, four feet deep, and eight feet long. At that rate, many farm woodlots would soon have been exhausted. Uninhabited areas beyond farming villages were cut over as well, their wood being sold as an export crop. (Even the Caribbean rum trade took wood from New England in the form of ship timber, kegs, and charcoal.) Thousands of acres were clear-cut and their logs skidded to the nearest stream, floated to navigable rivers, then shipped to New England cities, especially Boston, Providence, New London, New Haven, and New York, which had long since exhausted their local wood supplies. The city of New Haven alone consumed 7,500 full cords of wood in 1811.
Among other uses for wood, the making of "coal," the early American term for charcoal, took the greatest toll on New England forests at this time. Tens of thousands of acres, especially in the western highlands of Connecticut and Massachusetts, were cut for charcoal that was used in the blast furnaces of the early iron industry because iron refining required a hotter, more dependable fire than one produced by wood.2 "Coal" was made by hauling at least an acre's worth of timber to one site, piling it up in a giant, low cone, then burning the pile slowly beneath a smothering cover. Deforestation caused by charcoal production ended largely before the middle of the nineteenth century, when "real" coal—chiefly Pennsylvania anthracite—could be imported by canal and railroad. The steamships and steam railroads to come would consume wood for fuel as well. New England was headed down the path of Britain, which had been largely deforested since medieval times.
A shift toward sheep farming in the late eighteenth century also correlates with the construction of stone walls, many of which enclosed sheep. But there's more to the connection between sheep and stone walls than farmers containing their herds. Pastoral cultures in the Mediterranean—Italy, Greece, Albania, Cyprus, Palestine—had learned from experience just how damaging sheep and goats were on hillside land. Their narrow snouts, hard, cloven hooves, flexible lips, and strong teeth evolved for pulling plants out by their roots in rocky areas. There is an old joke that "New Hampshire raised sheep because only sheep had noses small enough to reach down between the rocks for wisps of grass." John Muir, founder of the Sierra Club, was so disgusted by their damaging habits that he dubbed them "woolly locusts." Sheep and stone walls go together not just because extra enclosures were needed, but primarily because the expanding flocks damaged the topsoil, which yielded a bumper harvest of stones.
Actually, stone walls made a poor fence for sheep, unless the wall was at least four and a half feet high and with almost vertical, if not overhanging, sides. Since all breeds of domestic sheep are descended from an ancestral herbivore whose very survival depended on climbing rock cliffs to escape predators, sheep feel quite at ease on stone, but are seriously intimidated by wooden barriers. In many cases, stone walls provided little more than a place for sheep to cavort, even for those strains purposely bred to have stubby legs. It is a rare sheep fence today that is made entirely of stone. Most have a strand or two of electrified wire.
The most important link between deforestation and stone walling, however, wasn't about wood, sheep, labor, technology, or even human volition. It had to do with changes in the soil caused by the absence of the forest itself. By drying out the surface, changing the pattern of snow cover, and reducing the insulating value of the topsoil, deforestation inaugurated a sequence of specific chemical, mechanical, and thermal processes that would inevitably make the soil stony.
The upland New England soils, almost all of which were developed on different types of glacial till, were particularly susceptible to these processes, much more so than either lowland sandy soils or those that were already quite rocky. This was because till soils were compacted below rather than above the surface and had a significant component of silt, rather than sand or clay Such soils are especially prone to frost heaving because the hardpan layer at depth traps infiltrating moisture and the silt promotes its dispersal, making these soils freeze easily and deeply when the ground is exposed to cold winter winds.
Although it seems counterintuitive, snowfall—particularly if it arrives early in the winter—mitigates the effect of frost heaving. Snow normally insulates the soil from the cold atmosphere and locks away moisture that would otherwise have seeped into the soil, where it could freeze and expand. Timothy Dwight observed that forested land, even at the latitude of northern New Hampshire, remained frost-free for much of the winter. "A stick forced through the snow in the month of February enters the earth without difficulty: the snow falling so early as to prevent the frost from penetrating the earth to any depth, and dissolving the little which had previously existed." But unforested land, even at the latitude of southern New England, freezes deeply; Samuel Deane remarked that: "Wlien the ground is bare, it commonly freezes to as great a depth as water does, which, in this country, is sometimes not less than 30 inches."
The importance of snow and mulch in regulating the depth of ground freezing has been confirmed by more than seven decades of continuous meteorological measurements at Hubbard Brook, New Hampshire, where the U.S. Forest Service maintains its most intensively monitored hydrologic research station in the northeastern woodlands. Since measurements began in the 1930s, forested plots in Hubbard Brook have seldom frozen deeper than a few inches, with the maximum depth of freezing (six inches) coming during the year with the least snow.3 In contrast, the depth of frost beneath nearby lawns and golf courses—the closest analog to an upland pasture during the late eighteenth century—exceeds two feet during many years.
Intense freezing wasn't necessarily seen as a problem by early farmers. In fact, Samuel Deane saw it as a benefit to the soil. "I suspect that our severe frosts in winter may have a tendency to excite a degree of fermentation . . . For the heaving and settling of the soil will make some alteration in the disposition of its particles, and conduces to its imbibing more freely, snow water and rains, which contain food for plants."4 Thus, he advised farmers to augment the freezing process by furrowing the soil deeply. This was accomplished by dragging a coarse, heavily loaded rake or cultivator in the soft soil, to produce a series of miniature ridges and valleys. This increased the contact area between the summer-warmed earth and the winter atmosphere, making the transfer of heat more effective. It also simultaneously helped shade and dry the soil. On the one hand, Sam Deane was correct, because freezing can help break up resistant clods of soils and create new voids for the infiltration of rain. But the benefits of freezing were skin deep; with the subsoil frozen and less permeable to the downward percolation of water, surface runoff and erosion were increased.
The more hostile winter climates of late-eighteenth-and early-nineteenth-century America also encouraged the ground to freeze deeply, just at the time when the land was most deforested.5 Mean annual temperatures during the half century of most active wall building (1775 to 1825) were colder and more variable than those of the present century. Exceptionally cold winters were noted when General Washington was at Valley Forge (1777 to 1778); during the period 1783 to 1785, when crops were ruined by summer frosts; and in 1816, the Year without a Summer, following the volcanic eruption of Tambora in what is now called Indonesia. Mean annual precipitation in the Northeast was also generally lower, as well, resulting, at times, in drier winters with reduced snowfall.
A cold climate at this time was not restricted to the northeastern United States, or even the Northern Hemisphere. It was a global phenomenon, the culmination of the Little Ice Age, an interval that began about A.D. 1100, when the Vikings abandoned their New World settlements. The Little Ice Age accelerated about A.D. 1300, peaked near 1850, and ended as the nineteenth century drew to a close. It may be no coincidence that the most intense decades of wall building occurred during this protracted period of colder, more variable, and drier winters, conditions that would have worked together to accelerate the heaving of stones from the soil.
Writing in America's first scientific monograph on soils, Nathaniel Shaler understood more than a century ago that frost heaving, which brought stones up, counteracted the burial of the stones by organic processes, which took them down. "As we shall see . . . this action of the frost is directly the reverse of that brought about by the work of plant roots and burro wing animals, which tend to remove the soil from beneath stones and to accumulate material on the surface in such fashion as to bury the masses."6
Frost heaving begins when liquid water, held on to soil grains by surface tension, freezes. Ice takes up 9 percent more space than an equivalent volume of water, ensuring that the soil expands during freezing. Since water in liquid and vapor phases is attracted, via a process called diffusion, toward soil that is already frozen, moisture is drawn up and adds to the amount of ice in the subsoil. Also, each speck of ice at the contact points between soil grains acts like a bridge, cementing the enlarging mass into a single, rigid body rather than a flexible, granular solid.7
As the frost line migrates downward, it reaches the tops of stones before it reaches their bottoms. When the bond between frozen soil and the top part of each stone is strong enough, the stone rises, creating a small void space at its base. Unfortunately for farmers and gardeners, however, two details of this "frost-pull" process are not reversible during the spring, when the fully expanded soil thaws and collapses back to where it started. First, although the soil must freeze from the top down, some of the thawing must proceed from the base upward, because the subsoil always contains residual warmth. This allows the soil adjacent to the void to flow into it while the stone above it is still frozen fast in position. The second nonreversible process is incomplete settling, which takes place during the final stage of thaw, when the frozen mass of soil that lifted each stone melts, softens, and subsides downward. The uplifted stone descends normally until its descent is blocked by whatever fell or squeezed into the hole. Being unable to descend, the stone has no choice but to move upward, punching its way through the soil settling around it.
Viewed from the perspective of the soil surface, the stones are being heaved upward. But this is only an illusion. When viewed from any other fixed frame of reference—such as the center of the earth—it is the land that is settling downward. The stone is, surprisingly, stationary.
A separate frost-heave process, called frost push, is effective at a shallow depth, perhaps ten inches or less. In this case, the cold is conducted into the ground more efficiently through the stone than through the more porous and organic adjacent soil. Hence, the base of a stone reaches the freezing temperature before the adjacent soil, nucleating the growth of ice that can push the stone upward.
The small upward movements caused by frost heave, although usually minor (less than a quarter of an inch), happen during every freeze-thaw cycle. At the rate of a quarter inch per winter, frost-heaved stones are ratcheted upward several inches per decade until they punch through the top of the soil. That's fast enough to make a century-old farm stony, but slow and hidden enough so that the process causing the stone to accumulate will be poorly understood.
After they were "born," the dirt-covered stones were usually washed clean by spring rains, giving the added illusion that they appeared almost overnight. Yankee farmers called them New England potatoes because they appeared like magical crops in fields that had been picked clean the year before. Others thought the stones grew from Satan's seeds. Nathaniel Shaler, a geologist, was one of the few who knew what was actually taking place underground.
The U.S. Army Corps of Engineers Cold Regions Research and Engineering Laboratory (CRREL), in Hanover, New Hampshire, is famous for its controlled frost-heave experiments. Using giant soil tanks within even larger refrigerators in their laboratories, CRREL scientists have watched stones heave upward more than five millimeters (a fifth of an inch) per day. They have also shown that heaving is more rapid where there is some slope, which enhances void closure, and where the soil contains some silt and clay, which enhances the holding and wicking of moisture. They have also shown that the physical attributes of each stone (shape, smoothness, density, size) make a difference: Rough, granitic, slab-shaped stones move upward faster than smoother, smaller ones; stones buried more deeply move upward more slowly because freezing takes place from the top down, and because the weight of the overlying soil holds uplifting stones down more effectively.
Another frozen-ground process, called thaw consolidation, accounts for increased stones at the surface. It takes place when void spaces in the subsoil produced by roots and animal life are destroyed by freezing faster than new ones can be formed by plants and animals. Thaw consolidation permanently shrinks the vohime of the soil, allowing the soil surface to descend downward onto the stones being "pulled" up from below.
The sequence of stone sizes and shapes that will appear in a Yankee pasture or field can actually be predicted from these frost-heaving experiments. Large erratics would already have been visible on the recently deforested surface. Slabs from the melt-out till would be next, because they heave most effectively. Then a mixture of slabs and cobbles—rounded stones intermediate in size, between that of a boulder and a pebble—wovild appear. Last to come up would be small, rounded pebbles. First there would have been few stones. Then the rate of new stones would have accelerated to a maximum, then decelerated more slowly. Eventually, only a few stones would rise.
Tillage, rather than pasture, would have intensified the process because the raw mineral soil is most exposed to winter's cold, freezing more often and more deeply. The same is true for heavily used pasture, when compared to less-worn-out pasture soil. All other things being equal, cultivation and heavy pasturing would have produced more stones, bigger stones, more rapidly arriving stones, and more rounded stones than less intensively used land. Land under protracted cultivation would have, in the final stages, produced copious loads of small, rounded stones ranging in size from bread loaves to rolls.8 Burning over the land prior to cultivation would have helped trigger frost heaving because the light color of the wood ash would have helped to reflect weak early-winter sunlight before the snows of late winter could insulate the ground. Thus, clearing, burning, tilling, and grazing would have awakened the stones from their thousand-year slumber as if they were bears being roused from hibernation.
This pattern of stone arrival was witnessed during the nineteenth century by an educated farmer named Hoyt from New Canaan, Connecticut, with a good sense of humor.9 He took the day off to give a speech at the sixth annual meeting of the Connecticut Board of Agriculture. In a technical session titled "Improving Rocky, Sandy, and Barren Land," he described how the frequency, size, and rate of stone production were related. "We found that after getting off the first crop of stone, there was another one underneath . . . and many times the second crop has been quite as large as the first one. Although perhaps the stones were not so large, yet there were enough more of them to make up the difference." Had Mr. Hoyt's stones kept coming at the same rate he witnessed during the first decade or two of clearing, similar areas of New England would now look like the floor of a bedrock quarry Fortunately, the supply of stones was limited by its original concentration in the ablation-till layer, which lay above the hardpan and below the biologically fractionated fine-grained soil.
Louis Agassiz
Louis Agassiz, a Swiss immigrant and one of America's most distinguished natural scientists of the nineteenth century, understood that the supply of stones heaving up from New England soils was finite, and would someday be exhausted. " . . . the ground has already been cleared to a great extent of its rocky fragments. . . . In the course of time they will, no doubt, disappear from the surface of this country, as they have done from that of Europe."10 The passage of time proved him correct, for those New England farms that stayed in business after the Civil War saw the abundance of stone diminish; it still kept coming, but more slowly and erratically.
The pattern of stone arrival suggested by these laboratory studies of frost heave, eyewitness accounts, comparisons with Europe, and contemporary predictions is that during the early years on pioneering homesteads there were few stones to be moved from pastures except for the largest. Within a few decades, however, stones began to arrive dramatically from their underground reservoir, making the clearing of stone an integral part of annual chores. Eventually, perhaps after a half century on tillage lands and a century of heavily used pasture, new stones declined as the supply from below was used up; those that could move had already done so.
Frost heave was not the only process responsible for concentrating stone. Loss of the topsoil through poor farming practices was another important factor. Cleared forest soils literally shrank in volume as the organic matter within them disappeared. Normally, under forested or grassland conditions, organic matter is added to the soil at the same rate it is extracted, and is recycled continuously among growing plants, the litter of leaves and twigs, and the topsoil. On farms, however, there is a net loss of organic matter because the biomass is physically removed through the harvesting of crops. This wasn't a problem until the volume of organic material in the soil, which had been accumulating for thousands of years, became depleted below some critical threshold. At this point, mulch or manure had to be brought in to maintain sufficient organic material and the limiting nutrients like phosphorus and nitrogen. Mamire could be, and often was, hauled to fields in wagons. However, it was easiest to import manure by penning the stock, feeding them hay, and letting the "black gold" fall where it might. Manure was so important to agriculture that it was stored in barns to protect it from being leached by rainfall.
Soil erosion or the physical removal of topsoil took place wherever the mineral soil was exposed but not deeply plowed, and where it was compacted, either in response to declining fertility or by livestock trampling it. The chief factor responsible for producing surface runoff was the fact that the ground was frozen more often and more deeply, creating a barrier to downward infiltration of snowmelt and spring rains. The worst-case scenario for surface erosion took place when a thick snowfall came late in the winter on land that had been grazed too intensively. If melt took place quickly, the water locked up in snow acted like a bullet in a loaded gun about to be triggered by warm spring rains. Runoff was a much less serious problem in late summer and early fall, when tropical storms and hurricanes struck the region.11
Cobble in a pasture with a stone wall in the background.
The "top-down" mechanisms of soil loss (reduction in mass, compaction, and overland erosion) brought the surface of the soil, inch by inch, downward onto the stones rising up from below. When these two surfaces met, and when the stones weren't hauled away, the ground surface transformed itself into a cobble. Such cobbles today are often concentrated in the corners of old fields because livestock, particularly horses, tend to cluster in the corners where they nibble the vegetation down to nothing, soften the surface mud by stepping around in it, and compact the subsoil with their hooves, reducing its infiltration capacity. When the inevitable rainstorm finally occurs, water collects on the surface and runs off in sheets. This washes away the soft, stirred-up material at the top, concentrating the stones into a cobble. Today we use the term "cobble" to describe a large pebble or small boulder, rather than a patch of stony ground. The colonial cobblestone street is thus a copy of a naturally formed landscape element.
The erosion of upland soils by colonial and then Yankee farming, and the stone walls that resulted, is well illustrated by a study in the village of Lebanon, in east-central Connecticut, just inland from the coastal town of Norwich.12 Hilly terrain, originally mantled with typically loamy soil, Lebanon was occupied by the Mohegans before being deeded to a collective of colonists in 1692. Founding of the town, with 350 settlers, took place in 1695. As early as 1711, there were cattle drives to Boston, indicating that a pasture-based economy was already in place. Water management associated with dams and mills began shortly thereafter. The road network was essentially complete by 1734. By 1796, and with the population already in decline, there were more than 13,700 acres of cattle pasture on the town's tax list. Lebanon peaked earlier than most New England towns.
Topsoil washed downhill from pasture and tillage soils overwhelmed nearly every small hollow at the heads of streams. Countless small valleys below the hollows were converted to swamps, the drainage having been worsened by sedimentation. The small, perennial streams draining the swamps had their beds raised as much as six feet in the seventeenth and eighteenth centuries, creating broad floodplains that were ditched and drained as colonial mowing grounds. Intensified annual floods caused several small ponds and marshes to be completely filled by mud. The bottomlands of Lebanon and thousands of places like it in southern New England were effectively created during the colonial and Yankee eras as sediment washed off pastures and fields.
During intensive use of Lebanon's land for grazing and farming, the soil at the surface changed almost everywhere. The lowlands filled up with sediment washed off slopes, whereas the slopes became stonier, promulgating the construction of walls. Today, there are more drylands (walls and cobbles) and wetlands (filled valleys) than there were before people got involved. Both have evolved from a once more uniformly distributed thicker soil. The land, however, is not degraded. Instead, it is more ecologically diverse, more lived upon, more like that of Britain.
Seemingly wanton destruction of soil greatly concerned early European travelers, who, after living for centuries in one place,
knew that soil needed careful attention. The eighteenth-century Swedish naturalist Peter Kalm was particularly appalled:
After the inhabitants have converted a tract of land into a tillable field, which has been a forest for many centuries, and
which consequently has a very fine soil, the colonists use it as such as long as it will bear any crops; and when it ceases
to bear any, they turn it into pastures for the cattle, and take grain fields in another place, where rich black soil can
be found... But the depth and richness of the soil found here by the English settler misled them, and made them careless husbandmen.13
Illustration of an early plow.
By shifting around the location of tillage plots and pasture, New England farmers practiced something similar to swidden (also called slash and burn) agriculture, a technology usually associated with the notoriously poor soils of tropical rainforests, and which presupposes abandonment after a few years of use. Sometimes the American practice of abandoning one field for another went by the euphemism of "crop rotation," in which forest was taken for cropland, then given over to hay field, then to cow pasture, and finally to sheep range as its nutrient status declined. Some stony lands went through this sequence rapidly, being abandoned before their stones could be cleared away.
The plow is given far too much credit for bringing stones to the surface. A Vermont historical archaeologist recites the conventional wisdom: "When the land began to be plowed for fields, and the plow heaved up rocks, the problem of permanent fences was solved and . . . and New England's famed stone walls were begun." A more accurate view of the relationship between plowing and stone walling is provided by the ecologist David Foster: "These massive walls surround former cultivated fields where the collection of stones following plowing was an annual activity for all farmers, who added to and continually shaped these walls over long periods of time and through repeated years of use."14
Plows (then spelled "ploughs") did reveal stone in Yankee fields, but primarily because they penetrated slightly deeper into the soil than did the teeth of harrows, or the tread of human boots. But frost heave and other geological processes explain why farmers continued to find stones in fields that had not been plowed for years, and why stones showed up in places that had never been plowed. The exaggerated connection between stone and plow is retold through the generations because of its powerful symbolism; the stone, representing wilderness, confronts progress, the glistening plow. What actually happened is more interesting and ethically neutral.
Although stone walls were being built nearly everywhere in the half century after the American Revolution, they continued to receive little attention in farming manuals or in literature. For example, the longest statement on stone walls in Sam Deane s 1790 encyclopedia merely recommended using "stone of the slaty kind rather than pebbles [rounded stones], which . . . are a greater annoyance on a farm, as they need removing, but are not very good for any kind of building." The Reverend Peter Whitney, in his 1793 account—A History of Worcester County in the Commonivealth of Massachusetts: with a particular account of every town from its first settlement to the present time; including its ecclesiastical state, together with a geographical description of the same. To which is prefixed, a map of the country at large, from actual survey—mentions the use of stones as a fencing material in a few of the four dozen "townes," but has nothing more to say on the subject.
Men with oxen team clearing a large boulder.
Inattention to stone walls is also illustrated by Timothy Dwight's Travels in New England and New York (1821), a comprehensive and educated view of rural New England written when the upland pastures had been worked for at least
a generation, and when stone was much more noticeable. In thousands of pages he occasionally mentions the presence of a stone
wall, but provides only one full paragraph on the subject in his three-volume opus. In this paragraph, he describes the drumlin
landscape between Pomfret, Connecticut, and Worcester, Massachusetts:
An eye accustomed to the beautiful hedges of England would probably regard these [stone] enclosures with little pleasure .
. . A great part of what we call beauty arises from the fitness of means to their end. This relative beauty these enclosures
certainly possess, for they are effectual, strong, and durable... Indeed, where the stones have a smooth, regular face, and are skillfully laid in an exact line with a true front, the wall
independently of this consideration becomes neat and agreeable. A farm well surrounded and divided by good stone walls presents
to my mind, irresistibly, the image of tidy, skillful, profitable agriculture, and promises to me within doors the still more
agreeable prospect of plenty and prosperity.15
Reverend Dwight apparently could overlook the "rudeness" of stone walls only when they were put to use, and only when flat
stones were "skillfully laid in an exact line with a true front." Almost everyone else, notably Ezra Stiles, in his commentary
on his native Cornwall, Connecticut, focused on the bad side of the phenomenon:
Nature
Out of her boundless store,
Threw rocks together
And did no more.16
During the earliest years on farmsteads, stone was often heaped into piles, dumped in swamps, or stacked on ledges. Most of the stones moved during this stage were "two-handers," meaning that both hands were required to lift them. "One-handers" were usually ignored because they didn't interfere with the manually operated technology of the day, which was dominated by scythes for cutting grain and hay, shovels for digging, and separate forks for pitching hay and manure. Additionally, conventional wisdom held that small stones helped make soil more fertile. Some farmers actually worried that they would deplete the soil by taking too many of its stones away.
An exceptionally heavy stone or a load of smaller ones justified the use of a stock-drawn vehicle. A cart worked well on the firm ground of open pastures. On the rougher terrain of land being cleared, or on the softer terrain of cultivated fields, especially in spring, a stoiit wooden sled called a stone boat, or drogvie, was used. Made of flat-bottomed timbers bolted together, a stone boat was yoked to a team of oxen, attached to a whiffle tree (a device for distributing the force between the chains), loaded with stone, skidded to the edge of a field, and off-loaded. Such work was often done driving slack times, which was after harvests but before the ground was frozen, or during the interval between spring thaw and spring planting, when new stones were most visible.
Stone piles in the middle of pastures and fields were common during the first few decades of farming, and many still exist in the woods, especially on farms that were abandoned early on. But after a generation or two of farmers and their progeny, the edges of fields became the dumping ground of choice because the swath of land on either side of the fence had already been taken out of production; in this regard, the fence line was like a magnet for stone. At first, the stone was merely dumped in the weedy corridor, perhaps between the stumps of a brush fence, the rails of a worm fence, or the postholes. But eventually, so much stone accumulated that it was best managed by stacking it crudely, in order to conserve field space. This gave rise, almost automatically, to what is often called a tossed wall, in contrast to one that was fitted together, or laid. As they lengthened, individual segments of tossed wall would merge, a process that continued until entire fields were enclosed by a rough rim of stone. Thousands of "tossed" wall enclosures still survive.
To classify walls, it is important to make a distinction between the function of a wall and its structure. Functional walls include the retaining wall, the boundary wall, the estate wall, the stone fence, cattle guides, pens, foundation walls, cellar walls, and even walking walls, whose broad capstones were laid flat, like a sidewalk. Wall structure includes the single stack, in which large, often irregularly shaped stones are placed one upon the other; the double wall, in which slabby stones are slanted inward from two sides; and the disposal wall, in which two single walls are built several feet apart and the gap between them in-filled with stone. The degree of care with which a wall was built is also used to classify them. Dumped walls are those where the stones were randomly dumped. Tossed walls were given slight attention as individual stones were tossed into position. In laid walls, great care was given to selecting the stones and fitting them into an aesthetically pleasing "weave." Chinked walls had large gaps between the stones plugged with well-chosen or hammer-shaped smaller stone. Mosaic walls are those where large and small stones or dark and light stones were placed in a regular, often geometric arrangement. Copestone walls are those where the top tier of stone is laid on edge, rather than parallel to the ground surface.
The ecologist David Foster, having seen thousands of walls in Harvard Forest, distills all wall form, structure, and function
down into two basic forms:
Broadly speaking, there are two predominant types of stone walls. "Single" walls consist of simple lines of typically large
stones that usually enclosed pasture land. Since these fences served primarily to contain livestock and to separate lands
of different use and ownership, farmers seldom bothered to construct them in elaborate form or in size beyond that demanded
by their limited functional need. A second, much broader "double"stone wall often consists of well-formed parallel lines of
larger stones with the intervening space filled with many small stones. These massive walls surround cultivated fields.17
The vast majority of walls in New England are "tossed" walls, taking on either the "single" wall type—built around pastures for the expedient combination of stone disposal and fencing—or poorly built double walls. Most were initially viewed as quite ugly, especially by European visitors, who, according to landscape historian John Stilgoe, "disliked the stone walls because they seemed—and often were—poorly planned and poorly layered, liable to topple at the first frost, and certainly wasteful of space." Americans were not too proud of them either. Timothy Dwight apologized for their ugliness. Jess Buel, a widely regarded early agricultural reformer, recommended eliminating walls because they were of no vahie other than as a place to put the worst "obstructions to cultivation." The Reverend Dana Huntington wrote from his eastern Connecticut parish, "The land is deformed by immense craggy rocks . . . tottering stone walls with crooks and angles every few rods which rarely fail to attract the traveler unpleasantly." The historian Harold Fisher Wilson noted that "the stone walls and rail fences which outline [the fields] —they cannot by any stretch of the imagination be said to enclose them." In his 1939 book The Stone Industries, the mining engineer Oliver Bowles seems to have contemplated "strip-mining" stone walls as linear quarries, an action that speaks volumes about how he viewed them aesthetically.
The abundance of "tossed" (a.k.a., single) walls relative to laid walls is clearly explained by John Stilgoe:
The stone walls of New England... were built by men interested far more in land-clearing than in fencing. They piled the rocks
not in heaps but in rows equidistant from the center of their rectangular fields, along each edge. As with so many other features
of the American farmland, the [European] travelers misread the significance of the walls. American husbandmen looked not at
ragged walls or at stumps or girdled tress. Instead they focused on the emerging rock- and stump-free fields they called arable.18
Single wall (top); double wall (bottom).
Early fieldstone walls—those built before and shortly after the American Revolution on upland plateau farms—were ugly. Few were fences, either. Instead, they were primarily linear landfills, composed of nonbiodegradable refuse that was attracted to the edges of fields, as iron dust is to a magnet. Even Eric Sloane, who was reverent about all things colonial and early American, acknowledged that the walls were "little more than stones cleared from the fields that were piled neatly along one side." A century later, however, these stone dumping grounds would be appropriated as symbols of a vanished world.
Terrain without stone walls does not mean that the land was never farmed. Instead, it says more about the geological processes
that may have buried the stones—as much as several hundred feet beneath glacial lake sediments—than it does about human activity.
Conversely, a land parcel with massive, closely spaced walls says more about the thickness of the ablation-till layer than
it does about cultural practices or the intensity of the farm effort. Henry David Thoreau might have been the first to understand
how geological factors influence the location and layout of stone walls—in this case, in the hills of north Concord:
Excepting those fences which are mere boundaries of individual property, the walker can generally perceive the reason for
those [stone walls] which he is obliged to get over. This wall runs along just on the edge of the hill and following all its
windings, to separate the more level and cultivatable summit from the slope, which is only fit for pasture or wood-lot, and
that other wall below divides the pasture or wood-lot from the richer low grass ground or potato-field, etc. Even these crooked
walls are not always unaccountable and lawless.19
The pattern he recognized—separate lines of walls following the contours at high and low elevations—is governed by geology. The gracefully curved lodgment-till hilltops of the New England Plateau usually lack a thick cover of ablation till. Hence, there are fewer and more irregular boulders and their corners are often battered into smoothness. Stone walls there are usually well built, spaced farther apart, straighter in line, and less massive than those farther downhill, where the ablation till thickens, and becomes more discontinuous.
At middle elevations, the pattern is more complex. There, rain and snowmelt from highlands washed downward, where it merged with glacier water moving toward the sea; this produced torrential stream flow that washed away the till, leaving dense concentrations of stone. It is in these middle elevations that bedrock ledges are most common, giant erratic boulders are frequent, and where massive boundary walls are common, in part because there was so much stone so early.
At the lowest elevations, in small valleys, walls are often absent because they are buried by sand and gravel. If present, however, they are usually poorly built and substantially collapsed because the stones and boulders from which they were made are rounded, and therefore less stable to stack. They were of the "pebbly kind" rather than the "slaty kind," using the terminology of Samuel Deane.
Geographic location within New England, rather than elevation, also controls the abundance and style of stone walls. Boulders near coastal headlands, extending from Staten Island in New York to easternmost Maine, are generally rounded, having the shape of deformed cannonballs in some places, baking potatoes in others. Conversely, walls well away from the coast, in the granite highlands of New Hampshire and inland Maine, are often built of large, straight-edged, almost diamond-shaped stones because that is the way the homogeneous rock fractured after it solidified underground.
The spacing of walls and the way they are put together also is linked to the bedrock and the glacial geology. Excluding sediment-covered interval lands and lowlands, walls are most rare, and often most poorly built, on the terminal moraine of the southeastern fringe of New England. There, on the islands from Nantucket to Staten Island, the "bedrock" is composed of weakly cemented sandy strata rather than tough metamorphic and igneous rock; essentially, the strata of the coastal plain are too weak to produce boulders. Also, by the time the ice sheet reached the islands, nearly all of the stones within it had either been incorporated into the till or crushed to oblivion. The rounded stones that did survive the trip were diluted by the abundant sand. Hence, any walls built there were made with as few stones as possible, balanced precariously upon one other. Residents call them lace walls because they are made as much of air as of stones.20
This regional variant contrasts with the extremely dense concentration of well-made walls in places like Fairfield County, Connecticut, and Westchester County, New York. There the bedrock was tightly foliated, the glacier held a high concentration of basal debris, and there was little opportunity for meltwater reworking. Consequently, the walls there are massive, exceptionally stable, and well laid. They provide quite a contrast with the lace walls; they are impossible to see through. The difference in the pattern of stone walls from one region to the other doesn't reflect cultural choice as much as it does the abundance of granite over schist, whether the ice sheet was frozen to its bed, and how much meltwater was available.
The color of stone is also controlled by the geology. Near the edge of the Connecticut River Valley, the stones have the rich brick-red to maroon-brown color of the Jurassic deserts in which they were deposited; these were rocks from the rift basin. In Vermont, black slate is infused with white quartz veins, giving some of its walls a zebralike appearance; these were rocks from Iapetos. Walls in southeastern Connecticut and Rhode Island are pinkish, owing to the abundance of rose-colored feldspars in its granite; these are the ancient rocks of Avalonia. Large areas of northeastern Connecticut and central Massachusetts contain rocks that are rich in iron-bearing sulfurous minerals (pyrite, pyrrhotite, chalcopyrite) that rust strongly when exposed to the air, giving rise to yellowish-red stains that drip downward on the surface of otherwise light-colored rock; even quartz boulders are tinted orange. Most of the walls north of Narragansett Bay, Rhode Island, are dark gray in color, the neutral hue of the dirty, volcanic, sedimentary sandstone from which they were built. These walls sometimes contain fragments of coal and blackened fragments of plant fossils, speckling the otherwise dull color.
Stones throughout the region may be marked in curious ways. Flatirons are faceted stones, generally with a distinct flat face on one side. Such stones, after being tumbled about at the base of the glacier, were subsequently held firmly in place as they were ground down against smooth ledge, something similar to what happens when a stub of playground chalk is rubbed against a sidewalk. Some stones are drumlin shaped, smoothed on only one side. They were probably lodged in the till and held in place so firmly that their tops were eroded into egg shapes by the ice moving over them; their undersides remained flat or rough because the ice couldn't get at them. Other stones are bullet shaped, rounded on one end and flat on the other. They were made when a stone in the process of being pecked smooth by stone collisions was broken in half by something larger and harder. Scratches and gouges are most common on homogeneous, dark, soft rock such as argillite, which is essentially hardened mud-stone.
The hardest boulders in New England, those made of tan-colored quartzite, are often highly polished because they traveled long distances at the muddy contact between ice and rock, yet could not be broken. They frequently have crescent-shaped impact scars resembling the "smiles" on a poorly hit golf ball. Each smile records a powerful but nonlethal collision near the top of the accreting till layer. Sometimes a whole sequence of closely spaced crescentic fractures are lined up in a row, either on the bedrock or on a far-traveled stone. These are called chat-termarks. Each records a slight jerk, accompanied by a tiny earthquake, as two very hard rocks slid by each other incrementally. Something similar happens when a heavy piece of furniture is moved across the floor, its leg lurching audibly in tiny jerks—slip, stick, slip, stick, slip, stick . . .
Unusual marks on fieldstone, caused by weathering and glacial scratching.
Perhaps the most curious of all markings on stones are the straight, deep, narrow gouges. These marks often narrow in one direction or the other, or are parallel, or intersect at odd angles. The pattern looks like cuneiform script. Although these stones have been interpreted by antiquarians and amateur archaeologists to be ancient inscriptions, they merely record the erratic passage of a stone slab over hard, rough rock. Each gouge signals a point of contact and the passage of stone in a straight direction; a mark's change in direction records a shift in the direction of the stone being inscribed by the ice.
Stone walls say so much about the past. The geological thread of their history determined where stone walls would be built, and how the pieces would fit together. The historic thread determined the specific location and form of each wall. But something else was needed to turn copious stone into the ubiquitous stone walls of New England. Required was a greater share of prosperity and available labor.