90
Glacial sands and gravels extend beyond the till margin as pro-glacial outwash in the Cochester
area, particularly around Stanway and Birch (Fig. 2). In plateau areas, it is occasionally found
below the till sheet but where it does so occur, it is usually of minor importance, as at Newney
Green. This suggests that the glacier did not release much proglacial outwash over the plateau
area during its advance. Small amounts are found overlying the till at near Rayne, and between
Halstead and Wakes Colne (Ellison and Lake, 1986), probably associated with ice decay. The
most common occurrences of glacial sands and gravels are associated with the major valley
systems. A good example is the quarry at Ugley, associated with the Cam-Stort tunnel valley.
This suggests that the ice sheet primarily dewatered itself via the valleys and would explain why
there arc virtually none of the normal features associated with glacial limits such as outwash
plains and moraines. A low ridge of glacial sand and gravel between Brakes Farm and
Beckingham Hall near Birch which may be a terminal moraine (Ellison and Lake, 1986) appears
to be the only record of such features in Essex.
Fig 3. Inferred patterns of glacier movement in eastern England.
A - early Anglian ice advance; B - main Anglian ice movement. (After Rose, 1992)
Essex Naturalist (New Series) 16 (1999)