THE PENNSYLVANIAN PERIOD. 



Section in Northern Pennsylvania. 1 



557 



Names of Formations. 



Thickness 

 in Feet. 



Charac teristic s . 



■-* -' f Summit removed by erosion 

 j£.£l J Pottsville formation. . . . 



pS ^ I Sharon conglomerate. . . . 



200 

 60-100 



Sandstone, black shale, and fire-clay, with 



a three-foot coal-bed in the upper part. 

 White quartz conglomerate and sandstone. 



Unconformity. 







^ A r Mauch Chunk shale 



TS-2 1 Oswayo formation 



£« ^ I (Lower part of Oswayo prob- 

 es •£ I ably Devonian.) 



0-40? 

 1000 ± 



Red shale. 



Varicolored sandstone and shales. 





Section in Southwestern Pennsylvania. 2 



Names of Formations. 



i d f Summit removed by erosion 



<3.2 \ 



Dunkard series , 





& S { 



r Monongahela series 



Conemaugh series , 



Allegheny series 



Pottsville sandstone 



Unconformity. 

 Mauch Chunk shale. , 



Pocono sandstone. 



Devonian. 



Thickness 

 in Feet. 



400 + 

 380 ± 



590 ± 



270 ± 

 180 ± 



250 



300 + 



Characteristics. 



Blue to black limestone, weathering white; 

 coarse sandstone at the base; contains a 

 number of thin coal-beds. 



Blue limestone with calcareous shale-beds; 

 lentils of sandstone and coal; the most 

 important coal-bearing formation in south- 

 western Pennsylvania, and contains the 

 Pittsburg coal seam. 



Chiefly red and green shales, with inter- 

 stratified beds of coarse sandstone and 

 thin beds of coal. 



Shales, sandstone, and three important coal- 

 beds. 



Generally coarse hard sandstone or con- 

 glomerate, inclosing a thin irregular bed 

 of shale; equivalent to the uppermost 

 beds of the Pottsville formation in the 

 type locality. 



Red and green shales with beds of greenish 

 sandstone, inclosing a lentil of blue 

 fossiliferous limestone, which is the thin 

 edge of the Greenbrier limestone of 

 Virginia. 



Sandstone, varying from thin-bedded 

 flaggy rock to coarse irregularly bedded 

 conglomerate; beds of silicious limestone 

 at the top. 



Strata in broad gentle folds. 



1 Fuller, Gaines (Penn.) folio, U. S. Geol. Surv. 



2 Campbell, Masontown-Uniontown (Penn.) folio, U. S. Geol. Surv 



