﻿78 Geological Society. 



breaking up of the ice-foot, were spread over the lowlands, forming 

 the Low-level Lower Boulder-day. The climate then improved, al- 

 though subsidence still continued, and the sandy and gravelly de- 

 posits of the middle drift were produced — these deposits, at whatever 

 elevation they occur, having been found in shallow water during 

 the constant subsidence of the coast-line. The surface of the middle 

 Drift shows traces of what seems to have been subaerial erosion, 

 leading to the supposition that the land must have risen and suffered 

 denudation before that depression during which the Upper Boulder- 

 clay was deposited, at which period the climate again became ex- 

 tremely cold, and fresh glaciers were formed. Before the elevation 

 of the Upper Boulder-clay the climate was greatly ameliorated. 



8. " On the Preglacial Deposits of Western Lancashire and Che- 

 shire." By C. E. De Eance, Esq., E.G.S. 



The author believed that after the deposition of the Esker Drift 

 the country rose to from 200 to 300 feet higher than at present ; 

 but in the course of this elevation there was a pause, during which 

 denudation took place, and the low plains, now covered with peat- 

 moss, came into existence. Erom the consideration of the present 

 depths of the channel between Great Britain and Ireland, the 

 author inferred that an elevation of 200 feet would have caused 

 the coast-line to run from the Mull of Galloway to St. David's Head ; 

 and Ireland would have been so connected with Wales as to render 

 possible the migration of mammals, plants, and of man himself. 

 Glaciers probably still persisted in the lake-district during the whole 

 of this period of elevation. During a subsequent subsidence 

 drainage became greatly obstructed, peat was formed, the sea en- 

 croached upon the land and worked its way eastward over the sea- 

 bottom of postglacial times, a movement yet in progress. Here and 

 there sand has begun to blow, forming dunes. 



9. " Observations on Modern Glacial Action in Canada." By the 

 Kev. W. Bleasdell, M.A., Hector of Trenton. 



The author described some phenomena of ice-transport observed 

 in Canada, especially those produced by the flood, anchor, or pack-ice 

 produced in the rapids of the Canadian rivers. To this he attri- 

 buted the entire disappearance of Crab Island in the Biver St. 

 Lawrence, near Cornwall. This island occupied about an acre and 

 a half within the memory of men now living ; it has now entirely 

 disappeared, and the water above it is gradually deepening. The 

 island, according to the author, has been carried away piecemeal by 

 the action of miniature icebergs, floated off by a rise in the water 

 produced by a dam of anchor-ice below. 



