The underlying geology across much of the parish is formed of Lower Lias limestone and clay of the early Jurassic. The term Lias was first used by John Strachey in 1719 and is an old west of England quarryman's term applied to thin beds of muddy and shelly limestone, it was later extended and applies mainly to argillaceous (clayey) formations of the Lower Jurassic. The Lower Lias was formed by chemical precipitation within a shallow marine environment between 175 and 200 million years ago. Fossils are generally abundant with a wide range of animal groups represented.
Overlying the Lower Lias limestone
and clay, across much of the parish, are drift deposits of varying thickness
that have been deposited through glacial action. These deposits are referred
to as Boulder Clay which can be a confusing term in that the material varies
greatly in its make up, often containing sand, clay and larger erratic rocks
of a non-local origin. Rounded pebbles visible within the soils of the area
are a familiar site and represent many different types of rock brought into
the area from the north.
Sandpits Farm is so called
due to the localised sandy deposits that occur within the more elevated
parts of the parish. The sand has been quarried on a very small scale
for local building works into the modern period but probably also
exploited in the post medieval. It probably occurs in small patches of
variable coarseness and quality. I have observed some very fine sands
from these deposits.
Most of the
soil across the parish belongs to the Evesham 2 association. These are
typical calcareous pelosols (clayey soils) but can vary locally due to
the inclusion of material derived from underlying drift deposits. Small
areas of Denchworth soil exists to the south east, this being defined
as pelo-stagnogley soil - basically clayey and occasionally
waterlogged. Where sandy glacial deposits mix with the heavy Lias
clays, very workable and fertile soils occur. This may, in part,
account for the early origin of the village.
Archaeological Surveys, PO BOX 2862, Chippenham, Wiltshire, SN14 7WZ
All images and textŠ David Sabin & Kerry Donaldson