AMERICAN GEOLOGY DECADE OB" 1840—1849. 367 



together with the unfinished manuscript relating* thereto, passed after 

 his death in 1850 into the custody of the Smithsonian Institution, by 

 which it was handed over first to Agassiz, and several years later to 

 James Hall, to be put into shape for publication. For reasons unknown 

 to the public this work was delayed year after year, until, after the 

 death of Hall, in his turn (in 1894), it once more came into the pos- 

 session of the Institution. In the meantime all that was new had been 

 elsewhere described. Thus, through sheer neglect, Troost was robbed 

 of much of the credit to which he was justly entitled. 



In 1842 Dr. Edward Hitchcock read an important paper before the 

 Boston meeting of the American Association of Geologists on the 

 Phenomena of the Drift in North America, which is particularly inter- 

 esting at this time as showing the gradual evolution of 



Hitchcock on Drift rt & ~ 



Phenomena in the present theory from that of the Noachian-deluere 



North America, 1842. l * . , , . & 



idea advocated by earlier writers. Hitchcock s views 

 had, of course, been influenced by those of such men as Charpentier, 

 Agassiz, Buckland, and Murchison, and he expressed at the outset the 

 conviction that nearly all geologists would "agree in the principle that 

 the phenomena of drift are the result of joint and alternate action of 

 ice and water.'' To express this joint and alternate action he made 

 use of the term " glacio-aqueous." 



In this paper Hitchcock devoted some 50 pages to a description and 

 discussion of, first, transported bowlders; second, smooth, polished, 

 and striated rocks; third, embossed rocks; fourth, valleys or erosion; 

 fifth, moraines; sixth, detritus of moraines; seventh, deposits of clay 

 and sand; eighth, contortions of the stratified deposits; ninth, terraced 

 valleys; tenth, fractured rocks; and eleventh, organic remains, after 

 which he proceeded to discuss the theories of the various European 

 authorities and state his agreement or objections to the same. He 

 objected to the theory of Lyell to the effect that the results observed 

 by him in North America were produced by. floating icebergs derived 

 from glaciers formed on mountains as the land gradually emerged 

 from the ocean, because, first, it failed to account for the lower tem- 

 perature which was necessary; second, because there was no evidence 

 that the glaciers descended from the mountains; and third, because 

 the deposits of vegetable matter derived from land plants showed that 

 the continent must have been above sea level long before the drift 

 period. The theory of De la Beche, which supposed the contents of 

 the northern ocean to have been precipitated over the countries farther 

 south by the elevation of the polar regions, Hitchcock regarded as 

 possibly applicable to the low countries of Europe, but not to New 

 England, since it would require a rise of the ocean amounting to some 

 6,000 feet, and he could find no facts to justify such an assumption, 

 although recognizing the fact that the aqueo-glacial agency had operated 

 well over the summits of the White Mountains. 



