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NEW YORK STATE MUSEUM 



represents a deposit in a long submeridional Appalachian trough. 

 Its pebbles of coarse and fine gneiss came from a short distance 

 and the numerous Lower Cambric pebbles probably from places 

 north of the plateau. Its deposits suggest those of an embayment 

 receiving its materials from the north. The entire absence of the 

 fossils occurring in the nearby Becraft mountain formations favors 

 this conception of estuarine conditions. 



The evidence compels us to grant that the Rensselaer grit is of 

 later than Siluric ag'e ; there is some good reason for regarding it 

 an eastern deposit contemporary with the early Devonic, but the 

 alternative proposition stands open, that its estuarine character 

 and great thickness suggest identity with the Catskill beds which 

 stand sheer on the other side of the Hudson river in hights of 

 several thousand feet and only 30 miles away from the outlier at 

 Austerlitz. 



b Dana indicated by the term "Worcester trough," a hypothetical 

 Appalachian waterway in which the Carbonic beds of Worcester, 

 Mass., eastern Massachusetts and Rhode Island were deposited. 

 This is a more easterly northeast-southwest passage than the Con- 

 necticut trough and we can derive no satisfactory evidence of its 

 existence during the Devonic. Indeed the statements made above 

 indicate that, though this region may have been receiving 

 deposits (luring the Cambric, it was a land body during" the period 

 with which we are now concerned and was not opened again for 

 the reception of sediments till the beginning of the Carbonic. We 

 are compelled therefore to dismiss the Worcester trough as having 

 any bearing, from present evidence, on the theme before us. 



c The Perry-St John-Annapolis Devonic channel, lying further 

 to the south and east of those we have considered, is today repre- 

 sented by deposits still largely covered by the sea. Its far easterly 

 course and its isolation seem to indicate that it had nothing in 

 common with the rest, that it must have entered the southern 

 Appalachians by a way of which we know nothing. 



12 We are thus impelled to conclude from the factors given 

 thai the line of passage southwestward from all the channel basins 

 we have specially discussed, into the New York Helderbergian- 

 Oriskanj channel was by way of the Connecticut trough ; that the 

 Gaspe, Dalhotisie, Aroostook and in a sense the Piscataquis-Somer- 

 >et channels were independent isolated passages for a part of their 

 distance only and that they converged eventually southward to 

 contemporaneous or successive unity. 



