NOTES ON THE OHIO SHALES AND THEIR FAUNAS 27 



CORRELATION 



The question of the correlation of the Ohio shales has long 

 been a mooted one and little or no light has appeared on the 

 subject in the last decade. In 1897 Williams* included the 

 upper part of the black shales at Irvine, Kentucky, under the 

 Mississippian and in 1909 Morse and Foerstef correlated the 

 lower part of these with the Ohio shales and the upper part 

 with the Bedford, Berea and Sunbury. In some recent articles 

 all of the Ohio shales are referred to the Mississippian. 



The species listed below are from within five feet of the 

 top of the shales. 



*Spirifer audaculus Conrad, *Camarotoechia sappho Hall, 

 Chonetes two sp. undet., Lingula cf. ligea, Coleolus cf. 

 gracilis, Loxonema cf. delphicola, Euomphalus, Pleuroto- 

 maria, Nucula cf. corbuliformis, Palaeoneilo constricta, Leda 

 cf. diver sa, Cypricardinia sp. undet., Macrodon hamiltonce, 

 Orthoceras cf. sicinus, Goniatites two species undet., *Palae- 

 osolen two species undet., Spathiocarais (Identifications by 

 Dr. R. S. Bassler excepting those marked *). 



There are no Mississippian elements in the faunas as far as 

 they have been investigated and this fauna from the very top is 

 characteristically Devonian. As this region had free communi- 

 cation with the east and probably with the west in early Miss- 

 issippian time the faunas would have had a strong Mississipp- 

 ian element if they had been of that age. 



The Hamilton age of the Olentangy shales seems to be 

 established, and as the top of the Ohio shales bears a distinctly 

 Devonian fauna, and as fish remains that are found no place 

 outside of the Devonian are pre erved throughout their thick- 

 ness, it seems that the shales must be classed as Devonian and 

 younger than the Hamilton. That the overlying Bedford shales 

 are Devonian cannot be so positively affirmed. As there is no 

 break in sedimentation from Ohio to Bedford and evidence 



*Amer. Jour. Sci., Ser. 4, III, 398. 

 fjour. Geol., XVII, 176. 



