PROCEEDINGS OF THE OHIO ACADEMY OF SCIENCE. 401 



man was associated with various animals which have either be- 

 come extinct or have retired to the arctic regions. Of these the 

 mastodon is specially prominent in the Mississippi Valley, and, 

 on the Atlantic coast, seal and walrus. So far as we can see, 

 the conditions of life here, then closely resembled those found 

 among the Esquimaux of Greenland and the northern part of 

 British America at the present time. 



CHRONOLOGY OF THE GLACIAL PERIOD 



The connection of man with the closing stages of the Glacial 

 period gives us the best attainable means for estimating his anti- 

 quity, though by this method we can reach only the minimum 

 age since man may have existed outside the glacial area for an 

 indefinite period before the time of the deposition of the glacial 

 gravels in which his remains have been found. But it is of 

 great interest to determine approximately this one fixed point. 

 From man's connection with the glacial deposits it follows that 

 all glacial studies have a bearing upon the antiquity of man and 

 upon the many philosophical theories relating to the development 

 of the human race. 



It is becoming more and more evident that the current esti- 

 mates concerning the antiquity of the Glacial period are ex- 

 travagant in high degree, having no basis in observed facts. 

 The uniformitarian theory advocated by Sir Charles Lyell has 

 been the basis of most of these extravagant calculations, whereas 

 recent investigations clearly show that geological changes do not 

 by any means proceed regularly and by infinitesimal stages ; but 

 that' long periods of relative quiescence are followed by periods of 

 rapid changes in which catastrophes are by no means absent. 

 The Glacial peroid was itself a catastrophe following upon the 

 slowly accumulated causes of the Tertiary period ; and the evi- 

 dence is now abundant that the close of this period in Europe 

 and America if indeed it has yet closed, did not take place until 

 a high civilization had established itself in Egypt, Mesopotamia, 

 and Turkestan. 



It can be only upon the basis of this Lyellian theory of 



