264 POPULAR SCIENCE MONTHLY. 



illustrations in Pennsylvania, Nova Scotia, Kansas, Nevada, and 

 Florida. 



Professor Hitchcock has studied the Quaternary or glacial deposits 

 with great success. His first publication upon the terraces and allied 

 phenomena of Vermont appeared while the old views of a submer- 

 gence, with icebergs, prevailed, to account for the phenomena. A 

 study of the glaciers of Switzerland in 1866 satisfied him of the 

 truth of Agassiz's theory; and whenever the opportunity came for 

 re-examination of the surface geology of northern New England, 

 the facts were found to require a different theoretical explanation. 

 He caused a thorough examination to be made of the Connecticut 

 River terranes by Warren Upham in the New Hampshire Survey, 

 and proved that all the high mountains of Vermont, New Hamp- 

 shire, and Maine had been glaciated by a southeasterly movement. 

 The ice came from the Laurentian highlands, pushed in a southern 

 direction down the Champlain-Hudson Valley, with a southeasterly 

 flow over New England and southwesterly over the Adirondacks; 

 the last two courses having been subordinate to the first. At present 

 the Laurentian hills are lower than the New England and New York 

 mountains overridden by the ice, and probably the same was the case 

 in the Glacial period. The best explanation of these paths is afforded 

 by the suggestion that a gigantic ice cap accumulated north of the St. 

 Lawrence, towering into the clouds so much that its overflow natu- 

 rally descended over the White and Adirondack Mountains. 



That glaciers should accumulate terminal moraines is axiomatic, 

 but no geologist before 1868 had ventured to suggest where moraines 

 might be located in the United States. In that year Professor Hitch- 

 cock delivered a lecture before the Lyceum of Natural History in 

 New York and the Long Island Historical Society in Brooklyn, in 

 which he affirmed that the drift deposits from Prospect Park along 

 the backbone of Long Island for its entire length constituted the 

 terminal moraine of the great continental ice sheet. This declaration 

 inaugurated a new era in the study of the age of ice. The geologists 

 in their several States found the terminal moraines, and the various 

 phenomena began to be classified according to new laws. The search 

 for moraines has resulted in a restatement of the incident of the 

 age of ice; more than a dozen successive terminal moraines have 

 been mapped between New York and Montana, which suggest to us 

 the existence of several glacial periods. In compiling a catalogue of 

 observations of the course of glacial strise by the United States Geo- 

 logical Survey, it was found that Professor Hitchcock had recorded 

 for New England as many as all other geologists had observed for 

 the whole country. 



Ushers are another interesting class of phenomena, and were 



