CHAPTER XI. 



THE TACONIC QUESTION. 



"Now, who shall arbitrate? 



Ten men love what I hate, 

 Shun what I follow, slight what 1 receive; 



Ten, who in ears and eyes, 

 Match me; we all surmise, 



They, this thing, and I, that; 

 Whom shall my soul believe?" 



It is presumably scarcely necessary to call attention to the fact that 

 the older rocks of the earth's crust are exposed, in a majority of cases, 

 only where this crust has been disturbed through such folding and 

 faulting as is incidental to mountain making. As a result of such 

 processes these older rocks are, in the main, considerably altered and 

 their origin as well as geological age at times quite indeterminable. 



The attempt to fix the base of the Paleozoic strata or, in other 

 words, to find a line of demarkation and division- between the non- 

 fossil-bearing and the most ancient members of the overlying fossilif- 

 erous strata has, therefore, proven a matter of the greatest difficulty 

 both in America and abroad. In Great Britain and on the Continent 

 manifestation of this is found in the voluminous literature relating to 

 Sedgwick's Cambrian and Murchison's Silurian systems. In America 

 a similar controversy was contemporaneously waged, which has come 

 down to history under the name of the Taconic question. 



In his report on the second geological district of New York, pub- 

 lished in 1842, Ebenezer Emmons gave his first detailed account of the 

 Taconic system. A review of the subject may well, therefore, begin 

 with this paper, though an occasional earlier reference may be 

 necessary. 



In his report for 1838 Emmons had stated that the Potsdam sand- 

 stone was the oldest sedimentary rock occurring in the vicinity of 

 Potsdam (New York) and that no rock intervened between it and the 

 primary. In this opinion, to which he ever afterwards adhered, he 

 was quite correct. Overlying the Potsdam sandstone and always in 

 the same order he found the Calciferous sandrock, the Chazy, Bird's- 

 eye, and Trenton limestones, the Utica and Hudson River slates, etc. 



An examination of the country at the foot of the Hoosac Mountains 

 in western Massachusetts showed what appealed to him an entirely dif- 

 ferent series resting, like the Potsdam, directly upon the gneiss, but in 



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