Geology Site Account

Site name: Rolstons Pit (site of), Writtle

Grid reference: TL 671 058

Rolston's Pit was a sand and gravel pit visited by many geological parties in the late 19th century. The pit exhibited a classic section of chalky boulder clay overlying gravel. Geologists at the time knew that the boulder clay was deposited by an ancient ice sheet but were unaware of its age. They were also unaware that the gravel beneath the boulder clay was laid down by an early River Thames (the Kesgrave Sands and Gravels), an idea that did not receive general acceptance until the 1970s.

A beautiful engraving of Rolstons Pit in the late 19th century showing boulder clay lying on top of Kesgrave Gravels is illustrated in the first edition of The Geology of England and Wales by H.B. Woodward (1876). Whitaker (1889) reproduces Woodward's notes which stated "At Rolstons, south-westward of Writtle Church, one of the best sections of the gravel with boulder clay above was seen, the latter resting irregularly on the former, of which a thickness of about 20 feet was shown".

The pit was still in existence in the late 1950s.

Engraving of Rolstons Pit in the late 19th century showing boulder clay lying on top of Kesgrave Gravels. Illustration taken from The Geology of England and Wales by H.B. Woodward (1876).