THE GLACIAL HYPOTHESIS 3°9 



between the place of origin and that of deposit lay the Taconie range 

 of mountains. " If," he wrote, " the boulders were once lodged on 

 the glacier, the ice and boulders must have been transported by a flood 

 of waters over the Taconie Mountains." 



In 1842 Dr. Edward Hitchcock, already referred to in connection 

 with Dobson's work, read an important paper before the Boston meet- 

 ing of the American Association of Geologists on the phenomena we 

 are now discussing, which is particularly interesting as showing the 

 gradual evolution of the present theory from that of the Noachian 

 deluge idea, advocated by the earlier workers. His views had evidently 

 been modified by the publication of Agassiz's work and by the writings 

 of Buckland, Murchison, Dobson and others, and he expressed at the 

 outset the conviction that nearly all geologists would agree in the 

 principle that the phenomena of drift were the result of joint and 

 alternate action of ice and water. To express this joint and alternate 

 action he made use of the term aqueo-glacial. 



In this paper Hitchcock devoted some fifty pages to a description 

 and discussion of observed phenomena, 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 temperature which was neces- 

 sary; second, because there was no evidence that the glaciers descended 

 from the mountains; and third, because the deposits of vegetable mat- 

 ter 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 further 

 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 oper- 

 ated well over the summits of the White Mountains. 



To Agassiz's theory, which supposed an immense accumulation of 

 ice and snow around the poles during the glacial period and a conse- 

 quent sending out of enormous glaciers in a southern direction, fol- 

 lowed by enormous floods of water and transportation of icebergs on 

 return of a warmer period, he likewise took exception, since he was 

 unable to conceive how such effects could be brought about. Nor, 

 indeed, could he understand how such causes could operate when the 

 land was rising from the ocean and the water consequently retreating, 



