Boulder Clay in Essex

Abstract

THE extensive deep sewerage works now being carried out under Mr. H. Tooley for the Essex County Council at Harlow have disclosed facts of considerable interest to students of glacial geology. The main sewer from Potter Street cuts through the hill of Boulder Clay between that place and Harlow at depths ranging up to 32 ft. The excavations and tunnels are entirely in the Boulder Clay, which assumes here an extraordinary till-like character, more so than in any exposure which has come under my observation in southern England. It is a black (rather slimy) clay, such as may well have been derived from the pounding up of Kimmeridge Clay, or Oxford Clay (as the latter is worked at the extensive works of the London Brick Company at Fletton, near Peterborough). Through this numerous chalk fragments are dispersed, and in the lower portions boulders (rounded, subangular, angular, and often beautifully striated) are met with in great quantity.