Animals Before Man 



That this occurred after the Glacial period 

 is apparent, because the bones of mastodons 

 are found abundantly in the old bogs and 

 meadows that were formed in the hollows 

 scooped by the glaciers or washed out by 

 streams flowing from the melting ice. Some- 

 times a careful study of the surroundings has 

 shown that the place where the bones lay was 

 an old beaver-pond, in which the great masto- 

 don was mired and perished. 



Had the mastodon lived here before the Gla- 

 cial period its bones would be found under, 

 or at least in, the glacial sand and gravel ; but 

 in the Northern States they occur in swamps 

 and meadows in the mud and peat derived 

 from decaying vegetation. 



It can only be said that there seems to be 

 an old age in the life of species as well as in 

 the life of individuals, when a species, a family, 

 or an order even, comes to an end without ap- 

 parent cause, simply because its race is run. 

 Why this occurs we do not know, and while 

 it is an easy matter to frame theories to fit the 

 case, these are not always satisfactory. 



272 



