506 J. G. GoodcJiild—On Drift. 



whicli may have found their way into the ice through a crevasse 

 or otherwise would also be distributed throughout the ice in the same 

 way as the accompanying stones. 



There must have been a time in the history of the great ice-sheet 

 when the waxing glaciers,, before they became entirely confluent, 

 projected so far seawards that their advancing ends would plough 

 the sea-bottom, pushing before them the whole of the loose accumu- 

 lations of mud, sand, and shingle, with their inclosed remains of all 

 the animals which had lived and died there since the preceding 

 glacial period, which may possibly have dated back to Pliocene times. 



Hence such a sea-bottom might be expected to include relics of 

 the various faunge that had inhabited the spot under the greatly vary- 

 ing changes of climate which probably came about between the two 

 glacial periods. Thus we might reasonably expect to meet with 

 traces of the successive occupation of the sea-bottom by the various 

 colonies of Lusitanian, Celtic, Boreal, and finally of Arctic species, 

 which would respectively obtain stations there as the successive 

 changes of temperature of the sea-bottom favoured the encroachments 

 of one province upon another. 



When the Glacial Period had so far advanced that the glaciers 

 began to join ends, the submarine moraines, which were pushed 

 before the glaciers, would find their way on to the confluent streams, 

 and thus the old sea-bottoms would come to be blended in the ice 

 with the vast quantities of detritus which were being borne outwards 

 from the high land. 



As the ice increased in thickness, the included marine remains 

 would follow exactly the same course as the associated stones, and 

 would be carried inland to high levels wherever they were so im- 

 pelled by the local set of the surface currents of the ice. 



Of course the shells would not go inland unless there were currents 

 setting landwards in some part or other of the ice, and it is equally 

 clear that unless one or other of these currents had somewhere 

 crossed the sea-bottom, or had received accretions from other currents 

 which had done so, no marine exuvias could well find their way 

 inland in the ice. 



Animal remains, whether fossil or recent, included in the ice-sheet, 

 may have drifted long distances without being greatly crushed, as it 

 would only be in those places where there was much inequality in 

 the pressures. upon the more easily fractured remains that they would 

 be at all broken. 



In the ice, away from impediments, the pressure upon them would 

 practically be equal in every direction, and they might, therefore, 

 drift for ages without being much the worse for their entombment. 



The case of the bodies of Dr. Hamel's three guides which were re- 

 covered after drifting forty years in one of the Swiss glaciers 

 (Tyndall's Glaciers of the Alps, p. 76); the instance of the knapsack 

 referred to by Messrs. Forbes and Geikie; and, still more to the 

 point, the glass bottle which drifted for ten years with the above- 

 mentioned knapsack (Occasional Papers, pp. 193-195) ; the geo- 

 logical hammer which Prof. J. D. Forbes lost for fifteen years in the 



