THE "GREAT ICE AGE." 123 



termination of the glacier, and a concurrent general up-lift- 

 ing or up bending of the whole of its submerged portion 

 might occur without even a partial rupture or crevasse 

 formation occurring. 



Let us now follow out some of the necessary results of 

 these conditions of glacier existence and glacial prolonga- 

 tion. The first and most notable, by its contrast with ordi- 

 nary glaciers, is the absence of lateral, medial, or terminal 

 moraines. The larger masses of debris, the chippings that 

 may have fallen from the exposed escarpments of the 

 mountains upon the surface of the upper regions of the 

 glacier, instead of remaining on the surface of the ice and 

 standing above its general level by protecting the ice on 

 which they rest from the general snow-thaw, would become 

 buried by the upward accretion of the ice due to the un- 

 thawed stratum of each year's snow-fall. 



The thinning agency at work upon such glaciers during 

 their journey over the terra firma being the outflow of ter- 

 restrial heat and that due to their friction upon their beds, 

 this thinning must all take place from below, and thus, as 

 the glaciers proceed downwards, these rock fragments must 

 be continually approaching the bottom instead of continu- 

 ally approaching the top, as in the case of modern Alpine 

 glaciers flowing below the snow-line, and thawing from 

 surface downwards. 



It follows, therefore, that such glaciers could not deposit 

 any moraines such as are in course of deposition by existing 

 Alpine and Scandinavian glaciers. 



What, then, must become of the chips and filings of 

 these outfloatiug glaciers? They must be carried along 

 with the ice so long as that ice rests upon the land ; for this 

 debris must consist partly of fragments imbedded in the ice, 

 and partly of ground and re-ground excessively subdivided 

 particles, that must either cake into what I may call ice- 

 mud, and become a part of the glacier, or flow as liquid mud 

 or turbid water beneath it, as with ordinary glaciers. The 

 quantity of water being relatively small under the supposed 

 conditions, the greater part would be carried forward to 

 the sea by the ice rather than by the water. 



An important consequence of this must be that the 



