328 REPORT OF NATIONAL MUSEUM, 1904. 



1 s^}< > and put forward certain of his own relating to the rate of back- 

 cutting of the falls. To these views H. D. Rogers, in the American 

 Journal of Science for 1835, took serious exception. He believed that 

 the channel below the falls had been formed in part as a diluvial val- 

 ley and by some far-sweeping currents which denuded the entire sur- 

 face of North America and strewed its plains and mountains with 

 bowlders, gravel, and soil from the north. "The passage of such a 

 body of water over the surface would deeply indent all the exposed 

 portions of the land. Rushing in a descent from Lake Erie to Lake 

 Ontario, from a higher to a lower plain, and across a slope like that at 

 Queenstown, it would inevitably leave a long ravine. 11 Commenting 

 on this, Silliman remarked in the same journal that an earthquake 

 might possibly be instrumental in producing at once such a crack in 

 the strata as would drain the lakes in a few days or hours, and to such 

 an agency might be ascribed the channel in question. (See Hall's 

 paper, p. 384.) 



Rogers was born in Philadelphia in 1808, being one of four brothers — 

 James B., William B., Henry D., and Robert Empie — all of whom rose 

 to distinction as geologists or chemists. When not quite twenty-two 

 years of age he became professor of chemistry and 

 |ogers.° f M " °' natural philosophy in Dickinson College, resigning in 



1831 for the purpose of going to Europe to complete 

 his studies. He returned to Philadelphia in 1833, and in the ensuing 

 winter delivered courses of lectures on chemistry in the hall of Franklin 

 Institute. 



In 1835 he was elected professor of geology and mineralogy in the 

 University of Pennsylvania, and was also appointed by the legislature 

 in the same year to make a geological survey of the State of New 

 Jersey, as already mentioned. In 1836 he was made State geologist 

 of Pennsylvania, and it is upon the work done in this connection that 

 his fame as a geologist chiefly rests. 



In 1857 he was made regius professor of natural history in the Uni- 

 versity of Glasgow, being the first American to thus receive a foreign 

 appointment. As was the case with his brother, W. B. Rogers, lie 

 was a good lecturer, with quiet, gentlemanly bearing, never failing to 

 make a favorable impression upon his audience. 



His work in Pennsylvania showed not merely great administrative 

 ability, but also the power of mastering fully the observations of his 

 assistants, making therefrom important generalizations. He was 

 unquestionably the leading structural geologist of his time. That his 

 generalizations and the theories he deduced will Dot in all cases hold 

 to-day in noway reflects upon his ability. In judging his work, as, 

 indeed, judging that of any of his predecessors and contemporaries, 

 one must take into consideration not merely the condition of knowl- 

 edge at the time, but also the conditions under which they worked. 



