lo8 Association of American Geologists and Naturalists. 



originally formed glaciers ; they often ground and remain grounded 

 for months, turned and moved in every possible position by the wind 

 and waves. They would scratch the bottoms of tlie valleys of the 

 ocean, and would cause the excoriated appearance which the rocks 

 present. In Mr Redfield's view, this agent of currents of water 

 was sufficient to account for many of the geological phenomena 

 which the earth presents. 



M. Desor could not conceive how the sides of the valley could be 

 scratched by this agent if the bottoms were. He exhibited speci- 

 mens of strata or scratched rocks from the glaciers of the Grindelwald 

 and Aar of Switzerland, from Essex county, this State, from Norway, 

 and from the terraces near Lake Ontario. They are all similar in 

 character — one cause must have produced effects so similar. It would 

 not do to say that one cause operated in Norway, another in Swit- 

 zerland, and still another on this continent. The effects were 

 brought about by the slow action of a mighty body. Glaciers have 

 been observed not only in the Alps but also in the polar regions. 

 In Iceland, glaciers exist for fifty miles in extent. Such being the 

 case, it requii-es no great effort to believe in the existence of a 

 glacier SOU or 400 miles in extent. It is only necessary that the 

 temperature should be lowered a inw degrees for them to exist. 



Commander Wilkes, United States Navy, late of the Exploring 

 Expedition, remarked that icebergs have a wide distribution; that they 

 were constantly changing their specific gravity, changing their 

 position — what was a side at one time would become the bottom, &:c. 

 In this way the variety of strise might be accounted for. 



Professor Silliman, with no view to object to the glacier theory, for 

 he desired to learn, asked its advocates to explain the existence of 

 glaciers in regions where there were no mountains. The theory as 

 applied to the Alps and other mountainous districts was good. 



Professor Adams, of Vermont, made a drawing of a rock of tal- 

 cose slate in the valley of Union Eiver, Vermont. It was rounded, 

 beautifully polished, and striated on its surfiice. Near the bottom of 

 the rock was a depression or hollow, and upon the side on which 

 the power, whatever it was, first acted. This hollow was not touch- 

 ed — it presents a rough and jagged outline. The body appears to 

 have struck the rock near its lower edge, and, through the resistance 

 made to its passage by the rock, to have been forced over it, polish- 

 ing and striating its surface. If water was the agent, it would 

 appear as if it should liave acted equally on the depressed or hollow 

 surface. 



Professor Hitchcock said the rock referred to by Professor Adams, 

 a representation of which was drawn upon the black board, was a 

 miniature representation of the mountains of New England. Moun- 

 tains Monaduock and Ilolyoke were prominent examples. They are 

 all rounded and polished with strife running in one general direction 

 over their surfaces. It was evident to his mind that whatever body 



