AGE AND STRATIGRAPHIC RELATIONS OF THE 

 OLENTANGY SHALE OF CENTRAL OHIO, WITH 

 REMARKS ON THE PROUT LIMESTONE AND SO- 

 CALLED OLENTANGY SHALES OF NORTHERN 

 OHIO 



AMADEUS W. GRABAU 



Columbia University 



The name "Olentangy shale" was given by N. H. Winchell 1 

 in 1874 to the light-gray soapy shales which underlie the Ohio 

 shale and are exposed on the Olentangy River and its tributaries in 

 central Ohio. Winchell regarded this shale as belonging with 

 the Huron shale which overlies it, but since his day this deposit 

 has usually been classed with the Middle Devonian, 2 and has been 

 made in a general way the equivalent of the Hamilton formation of 

 New York. The reason for such a grouping seems to have been the 

 fact that in northern Ohio a shale and limestone series lies between 

 the Huron shale and the Delaware limestone and so holds essentially 

 the position occupied by the Olentangy shale in central Ohio. I 

 have elsewhere 3 proposed to call this series in northern Ohio the 

 Prout series, from its exposures near the station of that name. In 

 the summer of 19 14 I made a detailed study of the several outcrops 

 of this formation in the region about Sandusky, collecting at Plum 

 Creek and paying special attention to the contact of the Prout and 

 Huron formations shown in the exposures at Slate Cut on the 

 Lake Shore Railroad, halfway between Sandusky and Huron, and 

 in the "Deep Cut," about a mile northeast of Prout Station. A 

 summary of my observations was included in the Report on the 

 Bevonic Formations of Michigan submitted toward the end of that 



1 Geol. Surv. Ohio, II, Pt. 1, pp. 287-89. 



2 The author prefers the term "Devonic" to "Devonian," but has changed it in 

 conformity with the usage of the Journal. 



3 "Olentangy Shale of Central Ohio and Its Stratigraphic Significance" (Abstract), 

 Bull. G.S.A., XXVI (1915), 112. 



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