IXXX PKOCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 898, 



deposited the material that filled up the narrow descending 

 fissures, thereby making a fairly level fioor in the caverns before 

 occupation. This material in every case, unless where there is 

 evidence of its having been subsequently disturbed, consists entirely 

 of such local materials as Avould be brought down by the streams 

 from the immediately adjoining higher ground. When the higher 

 caverns were first occupied by hyaenas, it is probable that there was 

 comparatively little ice or snow on the mountains, and many of the 

 animals which lived in the valleys and on the plains extending 

 from them were southern types. Gradually, however, as the cold 

 increased, northern forms appeared on the scene and a commingling 

 of the two groups took place. 



The geographical features in the west and north-west in later 

 Pliocene times may be briefly summarized as presenting high 

 mountainous areas in Wales, Cumberland, the South of Scotland, and 

 in parts of Ireland bordering the Irish Sea and St. George's Channel, 

 with extensive plains traversed by great rivers in the areas now 

 submerged, between the west coast of England and Wales, and 

 Ireland. The conditions here were then in every way suitable to 

 form feeding-grounds for herds of the great mammalia, and indeed 

 such as could never have been repeated afterwards in these areas 

 either in late Glacial or in post-Glacial times. 



Animals from the south-east could reach these north-western 

 plains across Cheshire and the lowlands in the centre of England, 

 and others from the south by the plains on the west coast of Wales. 

 In this way northern and southern animals would, in a sense, freely 

 commingle and be afterwards driven together to more southern 

 areas as the cold increased, and the conditions became more and 

 more unsuitable to them. At first, in the mountains bordering 

 these plains, when only their higher parts were covered with ice 

 and snow, glaciers would occur only in the higher valleys ; but, 

 as the cold increased, they would become confluent with those from 

 adjoining areas, and in time reach the plains and there coalesce to 

 form, perhaps, as suggested by some, one vast sheet reaching 

 across from England to Ireland. Most of the animals, ere the last 

 stage had been reached, would, of course, have disappeared from 

 those parts towards more suitable southern areas. 



That the foregoing is, in brief, the history of the incoming of the 

 Glacial period in the north-west is evident from the deposits which 

 have been found in and about the caverns, and in sections at 



