Discussion

Abstract

The P resident (Professor F. W. S hotton ) asked about the age of the spectacular ice-dammed lake and its causal ice in Cardigan Bay. He expected that the effects would be ascribed to the Würm glaciation. In view of the occurrence of glacial deposits in Cardigan Bay that were reasonably ascribed to the Riss glaciation and the probability that in this period, and also perhaps in the preceding Mindel, Cardigan Bay and Cardiganshire would be more fully glaciated than in the Würm, what evidence was there, if any, for glacial deposits preceding the Last Glaciation? The A uthor said, in reply, that the Irish sea ice stood at the mouth of the Teifi valley while the last remnant of the Teifi lakes remained. Presumably at that time the Irish Sea ice spread over the Cheshire plain. The Teifi lakes must therefore have ended a considerable time before the retreat of the ice from that northern area. There was no evidence of glacial deposits earlier than the glaciation that gave rise to these lakes and none as to which part of the complete glacial sequence this glaciation should be referred to. The earlier Cwmcoy course of the pre-glacial Teifi valley and the wide Dulais valley north of Lampeter might possibly have resulted from a much earlier period of glaciation, but in view of their dimensions, which were comparable with those of the existing or immediately pre-glacial Teifi valley, the author believed that they must have been fashioned at some time during the Pliocene. Mr