The sand deposits at Burythorpe were
deposited back in the Jurassic period (160mya). At the time, this area of
Yorkshire was covered by a shallow sea on the southern margin of the Cleveland Basin
(an important sedimentary basin of deeper water), and to the
north of an
area underlain
by a granite body known as the Market Weighton High which remained relatively stable
throughout the period in
contrast the Cleveland Basin
which was subsiding.
Reworking and winnowing of the quartz sand in a
tidally influenced setting
resulted in its high purity and uniform fine grain-size which make its properties so
unique in the region and an ideal foundry sand. Occasional storm events
deposited shell fragments, including sparse ammonites as lag
deposits. An
unusual feature are the massive sandstone concretions, some weighing over
twenty tonnes which occur sporadically through the deposit.
