60 F a . REPORT OF PROGRESS. E. W. CLAYPOLE. 



a cubic foot, and must consequently be picked off by hand 

 before the land can be cultivated. In this it differs from 

 the yellow flint, which breaks down into small pieces which 

 do not interfere with the plow. The white flint is also 

 very fossiliferous, the yellow flint being comparatively 

 barren, and its fauna may be examined on the huge stone- 

 piles which often skirt the fields along its outcrop. Owing, 

 however, to the square-fracturing and brittle texture of the 

 stone it is almost impossible to secure specimens without at 

 the same time carrying away a great weight of the stone. 



At a few feet above these white flint shales the Oriskany 

 sandstone appears in full force, the transition being appar- 

 ently abrupt though nowhere exposed. 



b£ 



Section of Lower Relderoerg rocJcs 



kany 

 Wh 



Oriskany sandstone. 



f White Flint shales 10 feet, ^ 



' Yellow Flint shale 80 " 



Black Cherty limestone, 8 " 



( Tentaculite bed, 



Polyzoon bed, 



Beyrichia granulata bed, . 



<J I Leptaena bed, } 348 



Clark's mill ^ Stromatopora bed, .... 150 " 

 ljime shales, i , 



Sphcerocy&tites bed, .... 



Rhynchonella bed, 



| Murchisonia bed, .... 

 I Beyrichia notata bed, . . . 

 Lewistown Limestone, massive, 100 u ) 



Full details may be obtained from the township reports. 

 The lime shale, though very persistent, is apparently absent 

 at the exposure under Half Falls mountain. 



The following section will enable the reader to compare 

 the Lower Helderberg rocks of Perry county with the ex- 

 posures in New York as given in the survey of the State : 



New York. Perry co. } Pa. 



Upper Pentamerus limestone. 

 Enorinital limestone, Flint shales. 



I >«lt liyris (Spirifera) shaly limestone, . . . 1 Lime shales> 



Lower Pentamorns limestone, . . . . ) 



Water lime, (Tentaculite limestone,) .... Massive limestone. 



It is difficult to correlate these two sections with any de- 



