Small-scale erosion features in the lowlands of Britain have only previousl
y been described from the Wirral, Cheshire. In this paper a suite of simila
r erosion forms located within a subglacial meltwater channel is described
and compared with those previously reported. The forms consist of almost li
near channels incised into soft Triassic sandstone bedrock to a depth of up
to 1.76 m and a group of scallops occupying a vertical rock face. The chan
nels show two preferred orientations, one parallel to the last (Late Devens
ian) ice flow and another transverse to the ice flow. Two possible types of
erosion processes are identified: (i) erosion by phreatic (below the water
table) subglacial water flow, which produced the subglacial gorge, channel
s orientated parallel to the ice flow, and scallops, and (ii) erosion by va
dose (above the water table) subglacial water flow, which produced the chan
nels orientated parallel to the local bedrock slope (transverse to the ice
flow). The implications for Late Devensian glaciation of the area are: (i)
deglaciation was accompanied by active ice; (ii) deglaciation was achieved
under warm base conditions; (iii) vertical ice thickness was greater than 4
0 m; and (iv) the hydraulic potential gradient was possibly orientated N14
degreesE at the formation of the features.