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NEW YORK STATE MUSEUM 



the accessory evidence is confirmatory of an age for these deposits 

 essentially equivalent to the Oriskany. 



Still farther south at the north line of Massachusetts is the well 

 known occurrence of partly metamorphosed Paleozoic fossils at 

 Bernardston, contained in a limestone and an overlying quartzite. 

 These fossils, of which I have had opportunity to examine large 

 series, are invariably distorted in the quartzite where they most 

 abound so that any resemblance they may assume is too often a 

 resemblance by distortion and a determination thereof carries a 

 large element of fiction and imagination. I believe, however, that 

 the conclusions reached long since by Whitfield in regard to the 

 age of these rocks, that the limestones with large crinoid columns 

 are Helderbergian and the quartzites above with distorted brachio- 

 \:o:\s are Oriskany, is as close an approximation to the truth as 

 the facts permit. 



We must now again call attention to the altitude of the Helder- 

 bergian and Oriskanian rocks in the Helclerberg- mountains of 

 Xew York. They stand in an escarpment facing the west, north 

 and east overlain by the great thickness of later Devonic consti- 

 tuting the Catskill mountains. Their faces are terraced faces of 

 erosion. Their former extent was in the directions which they 

 face. Beyond any doubt these rocks extended eastward of the 

 Hudson and into western Massachusetts. In the view of Prof. 

 B. K. Emerson, the ultimate authority on the crystallines of Massa- 

 chusetts, there was here in western Massachusetts an undoubted 

 Precambric north-south ridge whose position above water was in- 

 dicated by the presence of a Cambric quartzite fringing the greater 

 portion of the outcrops. This may have been and undoubtedly 

 was repeatedly depressed and elevated and the adjoining Silunc 

 masses brought to day but there are no antagonistic considera- 

 tions for not assuming that it was all transgressed during the 

 Devonic and these Devonic deposits removed entirely by erosion. 

 Toward the north of this region near the north line of the state 

 is a break in the Precambric ridge which is of considerable width, 

 extending into Vermont and this may have well served as a pas- 

 sage for Devonic sediment from Xew York into the Connecticut 

 trough. East of the Connecticut river there is only a limite 1 area 

 of Precambric near the Rhode Island line, extending south into 

 Connecticut along Pong Island sound. This is everywhere mar- 

 gined by a quartzite interpreted as Cambric, and this with the 

 fossil-bearing Cambric localities at Nahant, North Attlebury and 

 Braintree was raised into land and so continued through Siluric 



