AMERICAN aEOLOGY — DECADE OF L840-1849. 365 



deluge, the bursting- of dams, the sudden melting of a polar ice cap, 

 or even to cometary collisions with the earth. 



Agassiz's ideas were favorably received by the majority of workers 

 in Europe and Great Britain, though there was naturally a highly 

 commendable feeling- of caution against their too hasty acceptation. 

 As a reviewer in the American Journal of Science has put it: 



These very original ami ingenious speculations of Professor Agassiz must be held 

 for the present to be under trial. They have been deduced from the limited number 

 of facts observed by himself and others and skillfully generalized; but they can not 

 be considered as fully established until they have been brought to the test of observa- 

 tion in different parts of the world and under a great variety of circumstances. 



The effect of the publication was, however, soon apparent in Amer- 

 ican literature. Thus, in 1839 James Hall, then a young man of 28 and 

 just coming into prominence in connection with the geological survey 

 of New York, had, with all the confidence of youth, written upon the 

 glacial deposits as they had come under his observation. Such he 

 regarded as due to water action, but to the action of opposite and con- 

 flicting, rather than single, uniform currents. The great extent of 

 the deposits and the evidence of long-continued wear shown by their 

 materials proved to him that the force which produced them was not 

 violent and sudden, but continued for an indefinite period. 



Four years later (1843) Prof. Charles Dewey, writing on the striae 

 and furrows on the polished rocks of western New York, argued that, 

 while the bowlders of the drift indicated that a mighty current had 

 swept from north to south, the polishing and grooving might be due 

 to glaciers as described by Agassiz. 



Glaciers or icebergs and the strong current of waters — a union of the two powerful 

 causes — probably offers the least objectionable solution of tho^e wonderful changes. 



Though disposed thus to accept in part Agassiz's conclusions, Dewey 

 yet failed to realize their full possibilities. He could not conceive 

 how it was possible for a glacier to transport sandstone bowlders from 

 the shore of Lake Ontario to the higher level of the hills to the south- 

 ward. Bowlders of gravwacke removed from the hills in the adjoin- 

 ing part of the State of New York and scattered throughout the 

 Housatonic Valley furnished a like difficulty, since between the place 

 of origin and that of deposit lay the Taconic range of mountains. 

 "If," he wrote, '"the bowlders were once lodged on the glacier, the 

 ice and bowlders must have been transported by a flood to waters over 

 the Taconic Mountains." The Richmond bowlder train, concerning 

 which we shall have something to say later, was likewise a source of 

 difficulty in his acceptation of Agassiz's theory. 



At the April, 1811, meeting of the Society of American Geologists 

 and Naturalists Mr. R. C. Taylor exhibited and described in detail a 

 model of the western part of the southern coal field of Pennsylvania. 

 This he stated to be the first model constructed in the United States. 



