Ries — Geology of Orange County. 



441 



From Walden, the slates and sandstones reach eastward to New Windsor 

 and Newburgh townships, to the Hudson rivei\ Along the northern border 

 of the county, the sandstone beds are especially abundant, and conglomerate 

 layers also appear. 



The thickness of the Hudson river formation is difficult to determine on 

 account of the many folds and the heavy drift covering in that part of the 

 county where the formation is found. It is probably not less than 1,800 or 

 2,000 feet. Where it comes in contact with other formations the relations 

 are invariably those of unconformity, faulting or overthrust. These various 

 relations are noted in detail elsewhere, and need not be repeated here. 



< Organic remains. The exact age of these slates has been a matter of 

 considerable discussion, owing to the apparent scarcity of fossils. .Mather* 

 mentions a locality near Sugar Loaf village, west of the station, and at 

 Buhner's quarry, and states that a few specimens of " testacea " were found 

 (p. 369). He also mentions another locality near Walden. 



In 1885, Darton collected the following species from Buhner's quarry: 



Orthis pectinella. 



Orthis test udin aria. 



Orthis plicatella. 



Leptcena sericea. 



Ca ma i 'ella hem iplica ta. 



Strophomena altern ata. 



Streptorhyncli us plan umbona or S. fllitexta. 



Ti • inudevs co ncenti "mis. 



Those at Walden are found at the junction of beds of sandstone and 

 slate below the bridge. The species found were: 

 Leptcena sericea. 

 Orth is testudinaria. 

 Orthis pectinella. 

 Con ul aria Trentonensis (? ). 



Darton also mentions a new locality in the shales of the railroad cut at 

 Rock Tavern, where the rocks are bent into an overturned synclinal. The 

 fossils occur in the lower members, and are not included in the crumple. 

 The species found were : 



LepUena sericea. 



< )rtli is test udin aria. 



* Geology of New York, Part I., 1843, p. 369. 



