70 Kansas Academy of Science. 



THE GLACIAL EPOCH. 



By Albert B. Reagan. 



Discussion of Theories of Scientists Regarding This Interesting 



Period of the World's History — The Author Presents a 



New Theory — What Are the Critical Periods 



of the Earth's History, and Why 



DO They Occur? 



OF ALL SUBJECTS in geology, with probably the excep- 

 tion of the subject of evolution, the glacial epoch is the 

 most interesting, the most discussed, and one of the least un- 

 derstood. 



The questions: Why did the earth's climate change from 

 the universal tropical Tertiary to the frigid ice-drift climate? 

 Why did the animals, without respect to kind, seek shelter, at 

 the beginning of said epoch, in caves and in every conceivable 

 place, where they were overcome, as their fossil remains indi- 

 cate? Why did the then large tropical species allow the ice 

 drift to overtake them, instead of moving towards the equator 

 as it advanced? and What force lifted the water into the air, 

 which, when condensed, constitued those world-cloaks of frozen 

 water? are still in conjecture. 



Many theories, it is true, have been advanced to explain the 

 causes of the glacial climate of said epoch ; but a mere glance 

 at them will show that they all have objectionable points, the 

 deluge theory as the cause of the drift having already lost 

 credence. 



The theory advanced by many geologists and scientists, that 

 the change of climate was caused by the combined influence of 

 northern elevation in high latitudes, which elevation caused a 

 broad connection of North America and Europe in the higher 

 regions; of the sinking of the Central American lands, thus 

 changing the Gulf Stream from its present course into the 

 Pacific ocean, therefore depriving the North Atlantic of the 

 Gulf Stream's warming influence, and also of the tendency of 

 cold to perpetuate itself by ice accumulation, like the theories 

 that will be mentioned later, has many objectionable phases. 

 In the first place, the above-mentioned cause would not produce 

 an ice sheet one mile in thickness as far south as the city of 

 Des Moines, Iowa, which city is situated in the glaciated region, 



