6 GIRTY 



without fossils, except fishes, and the upper portion of the Bed- 

 ford is practically unfossiliferous. The lowest Bedford, how- 

 ever, often contains an abundant though somewhat limited 

 fauna, part of which has been illustrated by Herrick.^ It is the 

 middle and upper Cuyahoga faunas and those of the Black- 

 hand and Logan formations which should be correlated with 

 the Kinderhook, Burlington, and Keokuk groups of the Mis- 

 sissipi Valley. It is probable, however, that the Mississippian 

 is initiated with the Berea grit, because the Bedford fauna 

 comprises a well-detined group of species, quite distinct from 

 any of the Waverly or Mississippian faunas. The lower Cuy- 

 ahoga fauna, so far as it is known, is allied to that of the mid- 

 dle and upper portion. The supposed equivalent of the Berea 

 grit in northwesten Pennsylvania contains a fauna which is 

 without much question of a Mississippian type, and further- 

 more, both theoretically, and practically for mapping purposes, 

 the Berea grit is a satisfactory bed with which to initiate the 

 Carboniferous series. 



From Ohio the Waverly group passes eastward into north- 

 western Pennsylvania. There, in his reports on Crawford and 

 Erie counties, I. C. White - has called the several members by 

 different names. The Blackhand conglomerate is his Shenango 

 sandstone, and apparently the Logan group is represented by his 

 Shenango shale. His Meadville shale, Sharpsville sandstone, 

 and Orangeville shale are, respectively, the upper, middle, and 

 lower portions of the Cuyahoga shale. In this region the Sun- 

 bury shale is either absent or merged with the lower Cuyahoga. 

 The Berea grit of Ohio is White's Cussewago sandstone, 

 together with probably the Cussewago flags and Corry sand- 

 stone.^ 



From Crawford and Erie counties the Corry sandstone can be 

 traced eastward to Warren, where it lies approximately 500 feet 



' Sci. Lab. Denison Univ., Bull., vol. 4, iSSS, pi. 9. 



2 Second Geol. Surv. Penn., Rept., Qj, 18S1. 



'Many of these correlations have been pointed out by Stevenson (Geol. Soc. 

 Am., Bull., vol. 14, pp. 27 and 42) and also In- Wliite in his report on Crawford 

 and Erie counties, above referred to. The views expressed above arc based upon 

 my own field work, bv which the formations and faunas were traced from Penn- 

 sylvania over extensive areas in Ohio. 



