Extinct Pleistocene Mammals 415 



valleys amenable to the same forces of erosion as those of the present 

 day, until the streams finally reached the stage of senescence, and the 

 waters descended quietly without waterfalls, like the base-leveled 

 streams of southern latitudes at the present time. 



With such a climate, and with such adaptable and attractive phy- 

 sical conditions, nothing was wanting for the existence of a fauna of 

 the most diversified types. Indeed we know that the present fauna has 

 its ancestry in the Pleistocene. The Glacial epoch simply caused the 

 migration of the Pleistocene animals southward, and on the recession 

 of the ice-border allowed the same fauna to return to re-occupy the 

 renovated lands. It is needless to dwell on the change produced in 

 the local physiography by the ice dge. Suffice it to say that on the 

 retirement of the ice the present conditions, approximately, were 

 inaugurated. The river gorges were filled, the streams turned from 

 their courses, the granitic crags were thrown down and buried and 

 the whole country rendered more smooth. 



But the fauna had suffered somewhat by the glacial cataclysm. 

 Some of its largest species had become extinct, and some had become 

 so dwindled in number, or so reduced in vigor, that their post-Glacial 

 representatives are sometimes not recognized as the same species, 

 although probably genetically the same as the Pleistocene. Of these 

 extinct large mammals I wish to call your attention to a few whose 

 remains have been found in Minnesota. Some of these survived the 

 Glacial period, and returned to Minnesota and flourished during the 

 inter-Glacial and post-Glacial epochs. If we consider these remains 

 in the order in which they have been discovered they will appear 

 about as follows: 



1. Eliphas primigenius, the mammoth. 



It is well known that in Siberia and Alaska the remains of the 

 mammoth are common. It is but recent that an entire animal was 

 found incased in ice and the flesh preserved. This specimen was 

 photographed in its place and afterwards it was remounted in the 

 museum at St. Petersburgh in the attitude in which it had when 

 found. The remains of the elephant, which was without much doubt 

 only a southern species (or several species) of the mammoth of the 

 north, have been found over a wide extent of latitude in North 

 America, extending as far south as Mexico. 



The geologic and geographic relations of the elephant with the 

 Glacial drift, and his chronologic relations with man, have been the 

 subject of considerable investigation. There is abundant evidence 

 that the elephant inhabited Minnesota in late Pleistocene time. His 

 skeleton and especially his teeth, have been discovered in several 

 places. In general throughout the central part of the United States 

 the remains of the elephant and of the mastodon appear to have about 

 the same age, and it is certain that they both survived the vicissi- 

 tudes of the Glacial epoch by migrating toward the south where they 

 found more genial climate. 



In the case of the discovery of a tusk only, it is usually impossi- 

 ble to distinguish between the elephant and the mastodon, since they 



