EVOLUTION OF ELEPHANTS 375 



upon a bed of clay, broken slate, gravel, and water-worn 

 pebbles, reposed a nearly complete mastodon skeleton to 

 which the bones already found had belonged. Some other 

 missing bones were later on unearthed in another neigh- 

 bouring pot-hole. 



In this case, as in others where mastodon remains have 

 been found in or at the bottom of peat bogs or swamps, 

 Professor Hall rejected the idea that they had been en- 

 trapped there by wandering over the surface in search of 

 food, as in many cases extensive swamps are more treach- 

 erous at the edges than farther in, and large and heavy ani- 

 mals are usually extremely cautious about the sustaining 

 power of the ground on which they tread. Hence he was 

 disposed to reject a comparatively late date for the Ameri- 

 can mastodon, and believed that the remains had been 

 drifted into their present location during the Glacial Period. 

 Of this he wrote :* 



"At the close of the Glacial Period or at any time during 

 its continuance, the thawing of the ice would release any 

 objects frozen into the mass, and these would be dropped 

 upon the surface, or promiscuously distributed. If, by 

 some means, the body of a mastodon had become imbedded 

 in the accumulating glacier, the expansion and contraction 

 of the ice, the cracking and filling of these cracks with water 

 and its subsequent freezing, all these combined together 

 might dismember the bones in the remarkable manner 

 before indicated, causing a separation of attached or adja- 

 cent portions in a way that no other means could accomplish. 

 Thus, while the bones constituting the greater part of the 

 skeleton remained in close proximity, and were deposited 

 in the deep pot-hole as found, other portions which had been 

 abruptly separated by the expansion due to freezing and 

 thawing were deposited in other places more or less distant." 



*Op.cit.,p.l06. 



