GLACIAL EROSION AND TRANSPORTATION. 253 



enough, lower down the valley, or issuing midway of its front 

 end in the mass of the terminal moraine.* 



It is urged, both against the foregoing statement of facts 

 and their theoretical explanation, that observations in Green- 



Fig. 75. — Reverse side of the same pebble. 



land are irreconcilable with them. For it seems to be ad- 

 mitted that the surface of the great ice-cap of Greenland is 



* " Second Geological Survey of Pennsylvania, Z," p. xxv et seq. 



