Review of the New York Geological Reports. 369 



ammonius, (fig. 1, p. 365,) lnachus undatus, Cyrtoceras pilosum, 

 (fig. 4, p. 365.) Cameroceras Trentonense, (fig. 4, p. 368,) Ortho- 

 ceras multilineatitm, (fig. 7, p. 368,) O. Trentonense, Bellerophon 

 punctifrons, (fig. 5, p. 365,) B. profundus, Nucula injlata, (fig. 

 2, pi. 106, p. 366,) N. faba, (fig. 5, p. 366,) Pterinea undata, 

 (fig. 1, p. 366.) P. orbicularis, (fig. 3, p. 368,) Strophomena se- 



ricea, (fig. 1, pi. 105, p. 366,) Orthis leptamoides, Delthyris ? 



Atrypa extans, (fig. 6, p. 366,) A. bisulcata. The above are fig- 

 ured and described. 



The best localities for studying the Trenton limestone and its 

 fossils, are Trenton Falls on West Canada Creek, Fort Plains on 

 the Mohawk, Watertown on Black River, Glen's Falls on the 

 Hudson River, Plattsburg and Essex near Lake Champlain. Its 

 principal outcrop is along West Canada Creek and the Mohawk, 

 extending from three miles west of Little Falls up the valley of 

 the Mohawk to Boonville, thence down the west and south ter- 

 race of Black River to Lake Ontario. It usually rests either on 

 the calciferous sandrock, or Birdseye limestone. In Lewis and 

 Herkimer counties it borders on the primary, but its junction can- 

 not be seen by reason of the diluvium. On the east side of the 

 primary range it appears only in isolated patches, on the west 

 shore of Lake Champlain, Glen's Falls, and a few other places in 

 the valley of the Hudson. 



Its greatest thickness is four hundred feet. To the east it 

 thins out and becomes blended with the overlying shales. 



Ores of lead and zinc are not uncommon in the east and west 

 joints of the Trenton limestone, hence Eaton's name of metal- 

 liferous limerock ; but they have not been found in profitable 



quantities. 



From the facts here given regarding the range of the organic 

 remains, it appears evident that the Trenton limestone has its 

 representative both on the Ohio and Mississippi Rivers, but as 

 there is some difference of opinion on this subject amongst geolo- 



be 



afte 



r. 



The Trenton limestone has usually been considered equivalent 

 to the Caradoc sandstone of England, but Dr. E. is inclined to 

 regard it as the American representative of the Bala limestone ; 

 in proof thereof he cites the following list of fossils from Murchi- 

 son's work, p, 308: Orthis anomala, SchloL, O. Actoniae, O. canalis, 

 0. compressa, O. Flabellulum, 0- lata, O. Pecten, O, protensa, 0. tes- 



