Lithology of the Chalky Boulder Clay

Abstract

The distribution of the Chalky Boulder Clay was established1 by 1880 and later Harrner2,3 concluded that the ice passed from the present North Sea across parts of the Lincolnshire Wolds, being deflected southwards by another stream from the Vale of York and fanning out into East Anglia and the Midlands. He believed a further stream of the same glaciation entered Norfolk across the present north coast coming in contact with the North Sea Drift (Cromer Till and Norwich Brick-earth). There has been long-standing controversy on the boundary between the two deposits and on the status of the Contorted Drift and Marly Drifts, which occur on the coast and a short distance inland in north Norfolk. There has also been much disagreement as to whether the Chalky Boulder Clay represents more than one major glaciation. On criteria of general description and erratic content6 and of stone orientations7, the co-existence of a lower Lowestoft and an upper Gipping Glaciation has been widely accepted for nearly 20 yr but recently this division has been seriously challenged8,9.