134 TRANSACTIONS OF THE [jUNE 6, 



Mountain. . . . Here an excavation has been made into the rock, 

 which is a dark-gray, argillaceous sandstone, indistinguishable from 

 the ordinary 'Hamilton flags.' Much of it is black with carbon- 

 aceous matter, but very little coal has yet been found, though the 

 workings have been carried on for some months. The point of 

 greatest interest, however, is the determination of the age of the 

 rock from its fossils. These are for the most part obscure, being 

 apparently mingled with the debris of a fragmental deposit ; but 

 enough has been obtained to fix the age as Devonian, and probably 

 of the Hamilton Group. The forms are Lepidodendron (probably 

 L. Gaspianum), Calamiles, Psilophyton, and, Dr. Newberry thinks, 

 Dadoxylon. 



" The prospect of obtaining workable amounts of coal is not by any 

 means flattering; but the scientific results are of much interest. 

 Professor Cook, in his recent report on the geology of Xew Jersey, 

 has considered this district to be lower Silurian, on the theory that 

 the series ascends regularly, in going westward from the Highland 

 range. "^ 



On the geological map of northern New Jersey, published in 1874, 

 this region remains colored as Potsdam, while the area called Hud- 

 son River group is given as Silurian Slates in the explanation of 

 the " Columnar section of geological formations in New Jersey." 

 Dr. T. Sterry Hunt stated in 1882 that he was disposed to regard 

 the Green Pond Mountain conglomerate "as a portion of the First 

 Graywacke or Upper Taconic."' 



The geological map of New Jersey, published in 1882,^ made no 

 change from the 1874 map for the Green Pond — Bearfort Mountain 

 region. 



In 1884 Professor John C. Smock revised the previous statements 

 as to the age of this terrane, and accepted the paleontological data 

 furnished by the New York investigations. In the New Jersey 

 annual report of that year the opening paragraph of Section VII, 

 on the "Devonian and Silurian rocks," states that "A re-examina- 

 tion of the rocks of the Green Pond, Copperas, Kanouse, and Bear- 

 fort mountains, and the adjacent outcrops of slate, limestone, and 

 gneiss, has brought out some facts which, taken in connection with 

 the observations upon the same range in Bellvale and Skunnemunk 

 mountains, in Orange county, New York, make it necessary to 

 revise the descriptions of these rocks. Their geological horizon is 

 not as low as was stated in the ' Geology of New Jersey,' in 1868, 

 or as has been represented upon the several issues of State geo- 

 logical maps."* Then follows a good review of the previous opin- 

 ions bearing on the age of this terrane ; but there is no mention of 

 Professor Martin's paper, which had evidently been overlooked. 



1 Proc. Lyceum Nat. Hist., New York, vol. I, p. 259. 



* Trans. Roy. Soc. Canada, vol. I, sec. iv, p. 254. 



3 Ann. Rept. State Geologist [New Jersey] for 1882. 



* Geol. Surv. New Jersey. Ann. Rept. State Geologist for 18S4, p. 29. 

 This work is credited to Professor Smock on p. 156. 



