REPORT OP THE STATE PALEONTOLOGIST 1902 1069 



rock with its fossils weathered out in relief is seen in a little 

 hillock in the southwestern part of the mountain, where it has 

 been brought up by fault no. 19. [See map] 



It is not possible to give the exact thickness of this formation 

 at Becraft. It can not be more than a few feet, and is probably 

 not much more than a foot. It grades below into the Port Ewen 

 limestone, but is abruptly overlain by the Esopus grits. The con- 

 tact between the Oriskany and Esopus is everywhere marked by 

 low swampy ground and by the existence of stream beds. A glance 

 at the map will show that the streams have all become adjusted to 

 the Oriskany bed, not so much because this rock is a softer one, 

 for, though commonly decomposed, the silicious portion stands 

 out in relief. It is rather due to the fact that the overlying 

 Esopus shales break up readily into a fine gravelly soil, which 

 is easily removed by the streams. The Oriskany and Port Ewen 

 act as a guiding plane along which the streams work downward. 

 The few departures from the characteristic method are explain- 

 able by local conditions of folding or faulting. 



9 and 10 ESOPUS AND SCHOHARIE GRITS 



These are dark chocolate-colored, gritty shales, with a com- 

 bined thickness of about 300 feet, of which about one third Is 

 considered as belonging to the Esopus. The dividing line is 

 drawn on lithic characters, w T hich are chiefly expressed in topo- 

 graphic features. The Esopus readily crumbles into small cubical 

 fragments under the influence of the weather, and hence presents 

 rolling surfaces, which commonly constitute the best farming 

 ground of the region. The Schoharie, on the other hand, resists 

 the weather more easily, but generally has its cleavage planes 

 well developed by the weather. These are commonly at a high 

 angle, and their presence obliterates the original bedding planes. 

 The topography of this rock is rugged, with numerous ledges, and 

 hence is generally left wooded. The best exposure of the Esopus 

 is above the contact line with the Oriskany on the west side of 

 the mountain. Here in the hillside above the stream, ledges of 

 the Esopus are visible. The Schoharie may be studied almost 

 anywhere over the area of its outcrop. Clarke has recorded the 



