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NEW YORK STATE MUSEUM 



at this place. The individual beds of sandstone do not seem 

 to be persistent except for short distances. There is found, 

 however, in a number of places in the Olean region a rust- 

 colored sandstone layer filled with limonitic concretions and 

 containing fish remains, but whether these exposures belong 

 to one persistent horizon or not is uncertain. To the southwest 

 near Warren Pa. fish remains are known to occur at several 

 horizons. 



Fossils. After the deposition of the Wolf creek conglomerate 

 which contains in its upper portion specially a marine fauna, 

 fossils rapidly disappear and the red and green shales and the 

 fine micaceous sandstones generally yield but few or, for con- 

 siderable intervals, no forms. In many places, specially in the 

 sandstones, fossils are entirely wanting. Conditions as a whole 

 were evidently unfavorable to animal life while these beds were 

 being deposited. Some fish remains occur as mentioned above 

 and the Salamanca and Kilbuck conglomerate lentils are 

 fossiliferous. 



Salamanca conglomerate lentil. The Salamanca lentil occurs at 

 about the middle of the Cattaraugus formation. It thins .out 

 and disappears to the eastward, not being known to occur on 

 the Olean quadrangle to the northeast of the Allegheny river 

 and Oswayo creek. South and west of this line it occurs in the 

 Olean area as a hard gray sandstone 10 to 15 feet thick, which 

 becomes coarser and thicker westward and passes into a massive 

 conglomerate on the Salamanca quadrangle. The sandstone 

 phase is well exposed in a number of small quarries on Mount 

 Hermon just south of Olean where it is locally known as the 

 Mount Hermon sandstone. It is there a medium to a coarse 

 grained sandstone carrying an occasional small quartz pebble. 

 It is generally cream-colored to gray though some layers are 

 dotted with innumerable small rust-colored spots that have 

 resulted from the decomposition of iron pyrite. The bedding 

 here is usually regular and the thickness of a. given bed uni- 

 form for at least some distance. The layers of from 8 to 16 

 inches in thickness are separated by thin shale films or partings 

 that render their removal easy. It weathers into hard, white, 

 parallel-sided blocks ihat are pierced by many vertical fucoid 

 tubes or stems. These fucoids are often very prominent and are 



