3^8 REPORT OF NATIONAL MUSEUM, 11)04. 



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



ice and snow around the poles during- the Glacial period and ;i conse- 

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

 lowed by 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 con Id 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, as 

 it must have been, to account for the various observed phenomena — 

 such phenomena as would necessitate the occurrence of water loaded 

 with ice and detritus floating for centuries at least over a large part 

 of the earth's surface. 



He likewise objected to Maclaren's "ingenious amalgamation" of 

 Lyell and Agassiz's theories, but failed himself to suggest one per- 

 fectly satisfactory. 



His paper showed a very clear insight into what had taken place, 

 but an inability, with the information at that time available, to account 

 for it in a satisfactory manner. Thus, in describing the striae found 

 by himself on the top of hills and mountains like Monadnoc, he wrote: 



Could immense icebergs have been stranded on the northern slope of the hills and 

 afterwards, by the force of currents, have been driven over the summits; or would 

 it he necessary to suppose that, after the stranding, the water must have risen so as 

 to lift up the iceberg; or would a vast sheet of ice lying upon the earth's surface, by 

 mere expansion, without the presence of water, have been able to produce the 

 smoothing and furrowing in question? 



He regarded the moraines as deposited by floating icebergs and the 

 linear forms observed as identical with the osars of Sweden. The tine 

 blue stratified clay, often overlaid by sand, so characteristic of the 

 upper valleys of the rivers in the glaciated areas, he regarded as silt 

 deposited in temporary lakes formed by the damming of valleys by 

 drift materials. After considering the phenomena as observed by 

 himself and weighing all the theories advanced from time to time 

 by the authorities quoted, he summed up the matter in the following 

 words: 



Is it not possible that the phenomena of the drift may have resulted from all the 



causes advanced in the theories under consideration. * * I feel * that the 



proximate cause of the phenomena of drift has at last been determined, namely, 

 the joint action of water and ice. 



This is true Hitchcock conservatism. 



In 1842 an expedition under Captain Powell was sent out by the 

 Secretary of the Navy to survey Tampa Bay, Florida. Through the 

 influence of the National Institute, in Washington, 

 Ro n Hda s i8°2 k in T " A - C onraa was allowed to accompany the party for 

 the purpose of examining into the geology of the 

 region. Conrad remained on the coast sonic three months, his results 

 being published in the American Journal of Science for 1846. 



