THE SECTION AT SCHOHARIE, N. Y. 375 



Fossils abound in some layers of the Oriskany. They are 

 not obtained readily from unweathered rock and the weathered 

 rock affords usually only casts, which, however, show the in- 

 terior structure with extreme accuracy. Sometimes where the 

 decay has not caused complete removal of calcareous matter, ex- 

 quisite specimens are found, showing shell structure and internal 

 appendages of brachiopods. The forms are not numerous at 

 Schoharie, but many of them are such as to be attractive museum 

 specimens. Those commonly obtained are Spirifer arenosus, S. 

 arrectiis, Metaplasia pyxidata, Meristella lata, Rensselceria ovoides, 

 Megalanteris ovalis, Rhipidoinella musculosa, Eatonia singularis, 

 StropJieodonta Diagnifica, Hipparionyx proxirnus, Anoplotheca 

 Habellites, Platyostoma ventricosum. 



Lamellibranchs are not rare, but they are seldom obtained in 

 good condition. The only forms passing up from the Helder- 

 berg are the Eatonia and LeptcEiia rhomboidalis, the latter very 

 rare. 



THE CORNIFEROUS 



Everywhere throughout this region there rests upon the Oris- 

 kany a mass of shale, grayish, from 95 to 105 feet thick (by ba- 

 rometer). This is the Cauda Galli grit, the Esopus shales of 

 Darton, and forms the slope above the Upper Pentamerus cliff on 

 both sides of the Schoharie valley. Its bottom layer, 3 to 5 

 inches, is hard and forms the floor of the bench, protecting the 

 softer Oriskany, whose wasting has formed a subordinate slope 

 Much of the shale is fissile, this being shown on West mountain 

 where the slope is abrupt ; the upper portion is rather harder and 

 is jointed so as to come out in blocks, 3 or 4 feet by about 2 feet 

 and 8 to 1 2 inches thick. The Spirophyton is most abundant in 

 the upper part. The exposures near Schoharie are all imperfect, 

 the best being on West mountain : there are very few on the east 

 side where the pre-glacial erosion was very extensive. 



The Schoharie Grit, between the Cauda-Galli and the Cor- 

 niferous limestone, is rarely more than 6 feet thick and is ex- 

 posed at very few localities. It is an excessively hard silicious 

 limestone, containing much ferruginous matter and dark brown 



