Fieldstone

Fieldstone is a building construction material. Strictly speaking, it is stone collected from the surface of fields where it occurs naturally. Collections of fieldstones which have been removed from arable land or pasture to allow for more effective agriculture are called clearance cairns.

In practice, fieldstone is any architectural stone used in its natural shape and can be applied to stones recovered from the topsoil or subsoil. Although fieldstone is generally used to describe such material when used for exterior walls, it has come to include its use in other ways including garden features and interiors. It is sometimes cut or split for use in architecture.

Fieldstone is common in soils throughout temperate latitudes due to glacial deposition. In Canada and the northern United States, the advance of the Laurentide ice sheet pulverized bedrock, and its retreat deposited several dozen meters of unsorted till in previously glaciated areas as far south as New England and the Upper Midwest. Although a coarse layer of glacial ablation would settle on top of the deeper lodgment till, it was these more deeply set stones that would prove a persistent challenge for settled human agriculture because they would be frost-churned into surface soils during harsh winters.

Settled agriculture requires relatively fine and uniform soils for intensive use, and large rocks pose additional risks for agricultural machinery, which they can damage if not removed. Because the stones are widely disseminated, removing fieldstone is a widespread and costly activity in early agricultural settlement. To prepare fields for cultivation, farmers would need to remove these stones, which requires significant manual labor. Until the 19th century, fieldstone was removed exclusively by hand, often with whole families participating in this task. Depending on the harshess of winters, this task would need to be repeated whenever frost levels would churn new stones into soil surfaces. Thus, land with many fieldstones was and is considered marginal and is assessed for tax purposes well below land that is considered stone-free.

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