48 J. J. STEVENSON — LOWER CARBONIFEROUS, APPALACHIAN BASIN 



This recalls Doctor White's Huntingdon County section, as number 2 

 is very near the place of the lower impure limestone.* 



Eastern counties of the Allegheny plateau. — Returning now to the north 

 and following the eastern tier of counties on the Allegheny plateau, 

 embracing at the south the great anticlinal s of the Viaduct, Laurel, 

 and Chestnut ridges, one finds a succession which was to be expected 

 in view of Miller's discovery in Blair county. 



Mauch Chunk rocks decrease in thickness rapidly along the northern 

 border. Shales and sandstones onl}^ are reported from Bradford, Tioga, 

 and Sullivan counties. In the last, Franklin Piatt assigns but 25 to 

 140 feet to the whole series ; but this estimate is indefinite, including, as 

 it does, only the red shales and ignoring the greenish sandstones as well 

 as the underlying red shale which contains a limestone. In the Barclay 

 coal field of Bradford county the thickness is about 200 feet, shales and 

 greenish gray sandstones, f while in the Blossburg coal field of Tioga 

 I. C. White finds 245 feet of shales and sandstones. Passing over into 

 Lycoming count}^, west from Sullivan and south from Tioga, one finds 

 Mr Piatt's measurement of 75 feet at Mclntyre, but this includes onl}^ 

 the red shales, and his line of separation differs from that drawn by 

 Doctor White ; so that we may regard the thickness in the two counties 

 as the same, taking the larger estimate as preferable. A. Sherwood 

 asserts that the thickness in Lycoming county varies from 271 to 415 

 feet. Professor Lesley quotes in detail the observations of Abram Mej^er 

 in northern Lycoming, according to which the thickness is variable and 

 the section differs extraordinarily from that obtained by other observers. 

 According to Mr Meyer, the thickness sometimes becomes 353 feet, 

 though usually much less. The succession is 



Feet 



Shales 20 to 150 



Limestone and shale 50 to 75 



Shales 80 to 120 



A section very similar to that alread}^ found in Bedford and Fulton 

 counties, the limestone being somewhat thicker, while the upper shales 

 have lost much. The middle portion of the limestone is silicious, mass- 

 ive, and non-fossiliferous, the only fossils found occurring just below 

 this in a yellow ferruginous bed crowded with encrinal discs.J 



Clinton county adjoins Lycoming at the west. There, at Lock Haven , 

 Doctor Chance finds below the Pottsville 100 feet of red shale, 15 feet of 

 white and gray sandstone, and 3 feet of mixed limestone and sandstone, 



*W. B. Rogers: Annual report Geol. Survey of Virginia, 1839, p. 91, 



t Franklin Piatt : Report of Progress in Bradford and Tioga (G), 1878, p. 127. 



I A. Meyer, cited by J. P. Lesley: Final report, p. 1803. 



