CHARACTER OF MORAINES. 169 



[Illustrated by diagram.] Each glacier has upon its side such 

 a wall of loose materials, and when the two glaciers unite into 

 one, the two walls of the combined glaciers unite into one, and 

 instead of being on the margin of the glacier, they are on the 

 top. These walls of loose materials are called moraines. It is 

 a local name, given by the peasants to these loose materials in 

 the Alps, and that name has been adopted by geologists, and is 

 now current in the Avhole scientific world to designate these ac- 

 cumulations of loose materials which accompany the glaciers 

 upon their sides so long as they are single, but which may be on 

 the surface where two glaciers have united into one. Suppose 

 you had two rivers on which wood was floating, and those two 

 rivers should unite into one current, and suppose that the two 

 rivers, at their junction, should carry different kinds of timber, 

 when they united, you would have, along the middle, a mixture 

 of the two kinds of timbers, maintaining a middle course, while 

 the materials on the two sides would be of different kinds. So, 

 when two glaciers united, you would have in the middle a mix- 

 ture of the materials of the two moraines, while upon one side 

 you would have only the materials that fall from one mountain, 

 and on the other side only the materials that fall from the moun- 

 tain on that side. Now, as the mass of ice is not tumbling over 

 from one side of the valley to the other, but is a solid mass, 

 which moves steadily through the depression in the surface, you 

 see that there could be no mixture of the different moraines, 

 as would be the case with timber floating upon a river, but the 

 three walls of loose material follow an independent course. 

 Now, upon the sides of these Alpine valleys you can track these 

 lateral moraines for as great a distance as you can track the 

 loose materials which are at the bottom of the glacier and the 

 polished and scratched surfaces which accompany them. So 

 that here we should have a lateral moraine following the ice to 

 Meyringcn — that is, for thirty-eight miles from the origin of the 

 glacier — and the middle moraine, which moves upon the middle 

 of the surface of the glacier where the glacier terminates, Avould 

 drop from its edge and fall to the bottom and there form another 

 kind of accumulation. The three moraines fall in different 

 places, and there is a transverse wall at the end of the glacier 

 fi^rmed across the valley. You see that no river could form a 

 transverse wall across the valley through which it flows ; but the 



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