BIGSBY PALAEOZOIC BASIN OF NEW YORK. 443 



but not pointed out, by that highly esteemed State-geologist, Mather, 

 as having occurred before and near the period of the Shawangunk Grit 

 or Oneida Conglomerate, are situated among the wrecks of the post- 

 carboniferous catastrophe, and are therefore obnoxious to the gravest 

 doubts as to their real origin. Neither is a disturbance so timed 

 necessary to explain appearances. 



The localities referred to are on the River Rondout, a tributary of 

 the Hudson River, and Mount Becraft, near the city of Hudson, on 

 a spur of which eminence Professor H. D. Rogers met with an im- 

 portant section, which I have not seen. 



8thly. Because, if the great Canadian assemblage of strata, called 

 Oneida Conglomerate by Sir William Logan, but Hudson-River 

 group by Professor H. D. Rogers in conversation with me, should 

 be the latter, we have evidence, in its numerous alternations of vary- 

 ing breccias and conglomerates, that the disturbances (if any) com- 

 menced with the end of Utica Slate, and therefore at another and 

 earlier period than when the Oneida Conglomerate was thrown 

 down. 



J. D. Dana, the learned naturalist, who in extensive travel and 

 philosophical spirit is the Charles Darwin of America, I was very 

 lately gratified in no common degree to find, absolutely affirms my 

 two propositions in the following forcible words : — "All the various 

 oscillations that were in slow movement through the Silurian, De- 

 vonian, and Carboniferous ages, and which were increasing their fre- 

 quency throughout the last, were premonitions of the great period of 

 revolution when the Atlantic border, from Labrador to Alabama, was 

 at last folded up into mountains, and the Silurian, Devonian, and 

 Carboniferous rocks were baked or crystallized. No such event had 

 happened since the revolution closiug the Azoic period. From that 

 time on, all the various beds of succeeding ages, up to the top of the 

 Carboniferous, had been laid down in horizontal or nearly horizontal 

 layers, over New England, as well as in the West : for the conti- 

 nent, from New England westwards, we have reason to believe, was 

 then nearly a plain. There had been no disturbances, except some 

 minor uplifts. The deposits, with some small exceptions, were a 

 single unbroken record until this Appalachian revolution." This was 

 one of the most general periods of catastrophe and metamorphism in 

 the world's history. 



In speaking of parts of Wales and districts adjacent, Professor 

 Phillips (Memoirs Geol. Surv. ii. p. 207) might be the historian of 

 the palaeozoic deposits of New York. 



He uses the following language : — " All these districts, after hav- 

 ing been part of a sea-bed subject to continual or interrupted sub- 

 sidence, were displaced by one great system of mechanical forces 

 operating through one period of time." This is a close definition 

 of my views. 



Objections discussed. — As has been mentioned already, the two 

 propositions, which I have thus been endeavouring to maintain, are 

 not fully acquiesced in by the Professors Rogers and other eminent 

 geologists. We shall now enter upon the delicate task of both 



VOL. XIV. — PART I. 2 G 



