"MANUAL OF GEOLOGY" 



grand features of the earth was discussed in early papers 

 as well as later; the problems of mountain-making and 

 the phenomena of volcanic action, to which he devoted 

 much thought, are some of the other topics treated at 

 length. 



" But, as a geologist, he was not only a thinker and 

 writer in his study, but also an active observer in the 

 field. This remark applies obviously to the four years 

 with the Exploring Expedition, but further particularly 

 to the period from 1872 to 1887, when he was carrying on 

 the study of the crystalline rocks of the so-called Taconic 

 system, chiefly in western New England; also of the 

 glacial phenomena of southern New England (1870 et 

 seq.). The region included in western Connecticut and 

 Massachusetts, and extending westward into New York 

 and north to Vermont, was tramped and driven over 

 many times, until one might almost say that there was 

 hardly an outcrop accessible to any of the roads in this 

 difficult region that had not been visited, its rocks 

 examined, and observations recorded on the dip and 

 strike. These results and the conclusions derived from 

 them fill many pages of this Journal. Against the dictum 

 that all crystalline rocks, not volcanic, must be of pre- 

 Paleozoic age, he rebelled strongly, as against all similar 

 dogmatic treatment of scientific facts and principles. His 

 strength of feeling on this point was what largely prompted 

 him to spend so much time and strength in this investiga- 

 tion. 



" He was no less interested in the country immediately 

 about New Haven, especially as regards its glacial phe- 

 nomena. In 1870, he published a large memoir on the 

 geology of the New Haven region. The observations, 

 recorded in this paper, were made at a time when work at 

 his table was impossible and the open-air exercise brought 

 profit to health as well as scientific results. Twenty years 

 later, when again incapacitated from writing and close 

 thinking, he issued a small volume entitled The Four 

 Rocks of the New Haven Region, describing some of the 

 chief features of the region in popular form." * 



* From the memorial in the American Journal of Science, by E. S. Dana. 



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