358 POPULAR SCIENCE MONTHLY. 



imparts any entire exemption from the influence of authority, and 

 bestows complete independence from the tendency to " swear to the 

 words of a master." 



Of the New York geologists, Vanuxem alone, in his Geology of 

 the Third District, 1842, inclined to the glacial theory; the others — 

 Emmons, Mather, and Hall — advocated floating ice, the latter urg- 

 ing as a chief objection the absence of any great northern highlands 

 from which glaciers could extend southward. Prof. Henry D. 

 Rogers advocated De la Beche's view, of great catastrophic waves or 

 debacles of water and ice, produced by sudden uplifts of the floor of 

 a circumpolar ocean, and sweeping southward with tremendous power 

 over the middle latitudes. These views were presented by him in 

 1844, at the "Washington meeting of the geologists, and are to us a 

 most curious illustration of the old " cataclysmic " phase of geological 

 conceptions. 



Two years later Agassiz came to America, and at once set about 

 studying the ice evidences here, first in the White Mountains and 

 then around the Great Lakes. At the first meeting of the American 

 Association, in 1848, he presented his views as to the identity of our 

 phenomena with those studied by himself, Desor, and Guyot abroad. 

 His views were not very warmly received, however, and he did not 

 attempt their public presentation again for some years, turning his 

 attention more to the field of zoology. In 1850, in a work on Lake 

 Superior, he refers somewhat sharply to the prejudice that seemed 

 to prevail in relation to this subject. 



From this time, however, the aqueous theories began to be less 

 strongly presented; and a new generation of geologists was coming 

 on, largely under the training of Guyot and Agassiz, and more open 

 to their observed results. C. B. Adams, in 1850, presented a view 

 nearly akin to that adopted by Dana a few years later, of an eleva- 

 tion of the high northern latitudes, resulting in a southward-moving 

 glacial sheet, and a subsequent depression connected with its retreat, 

 to account for the stratified deposits. Professor Dana accepted this 

 doctrine in his presidential address before the association in 1855, 

 adding the " Terrace period " of partial re-elevation. Prom this 

 time he became the leader of the American glacialists, and his great 

 Manual, issued in 1862, carried these views into all the colleges of 

 the country. 



In 1857 Prof. Edward Hitchcock published an important treatise 

 on Surface Geology, particularly of the Connecticut Valley, in the 

 Smithsonian Contributions to Knowledge. In this paper he noted 

 the distinction, so important and now so familiar, between local striae 

 and those with the general southward course of the " drift." Two 

 years later his son, Prof. C. H. Hitchcock, extended this distinction 



