W. A. Verwiebe — Berea Formation. 



55 



Pennsylvanian Pottsville 35 ft.-200 ft. 



(unconformity) 



5 ft.-200 ft. 

 2 ft. 



80 ft. 

 Conewango 510 ft.-560 ft. 



Chemung 1120 ft. 



Mississippian 



Devon-Carbonif. 

 Devonian 



Cuyahoga 

 Berea sandstone 



j Knapp 



Regarding the Berea the author says : " It has not been seen 

 exposed in place in the quadrangle, but loose pieces of sand- 

 stone crowded with its fossils have been found at many points 

 in such position as to indicate that their parent bed immedi- 

 ately overlies the upper member of the Knapp formation, 

 whether that be conglomerate or sandstone."* In tracing the 

 Knapp formation to the south, it strikes one immediately as 

 not improbable that the Knapp is the northern representative 

 of the Venango 1st oil sand. This equivalence is admirably 

 substantiated by the fossils contained in them, both being char- 

 acterized by a Syringothyris fauna.f It follows from this that 

 we should look for the Berea sandstone at a higher strati- 

 graphic level. This interval is approximately 150 feet at a 

 point a few miles south of Tidioute. North of this point the 

 shales underlying the Berea come up from beneath and present 

 an eroded surface to the Pottsville. This erosion plane cuts 

 across successively older portions of the Riceville shales as it is 

 followed northward. The Berea is therefore absent in the 

 Warren quadrangle. This conclusion automatically eliminates 

 the Cuyahoga formation from the Warren section. The rocks 

 which have been included under that heading are stratigraphi- 

 cally the equivalent of the Riceville of I. C. White; and, as 

 far as we may be guided by our present knowledge, there 

 seems no good reason to change this name. 



Doubtless much work still needs to be done, before the exact 

 equivalence of the Mississippian and Devonian rocks of the 

 Appalachian and Ohio basins can be precisely established ; how- 

 ever, it is hoped that the facts set forth in the above discussion 

 may prove of some value in attaining this result. 



The sections I, L, and M are considered most important of 

 those platted in fig. 1 and are appended in greater detail for 

 those readers who desire more precise data. 



* Idem, p. 36. 



fN. Y. S. Mus. Bull. No. 69, p. 995, 1902. 



