BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 26, pp. 205-216, PL. 8 JUNE 15, 1915 



DIASTROPHIC IMPORTANCE OF THE UNCONFORMITY AT 

 THE BASE OF THE BEREA GRIT IN OHIO ^ 



BY H. P. GUSHING 



{Presented before Ihe Society December SO, 1914) 



CONTENTS 



rage 



I ntroduction 205 



Description 20() 



The Brooklyn channel 20f; 



The underlying formations 208 



Extent of the Berea sandstone • 20l> 



Ohio Berea a non-marine formation 210 



Uplift following the Bedford 210 



Importance of the unconformity 211 



Comparison with the Pottsville unconformity 21.3 



Conclusion 215 



Inteoduction 



In 1874 J. S. Newberry made the following statements in the Ohio 

 reports : 



"In most localities where the Bedford shale is exposed the upper surface is 

 \ery irregular, and it^ is evident that the formation has heen extensively 

 eroded by the agency which transported the beds of sand, now consolidated 

 into the Berea grit." - 



"The best exposures of the entire thickness of the Bedford shale are on the 

 Black River below Elyria. ... It will also be noticed here that the upper 

 surface of the shale is very irregular, showing that the currents of water 

 which transported the sand — now the Berea sandstone — cut away the shale, 

 then a red clay, in broad and deep channels. As these were filled with sand, 

 the under surface of the sandstone is very uneven and its thickness variable." ' 



This imconformity, noted so long ago by Newberry, is wide-spread, and 

 has attracted the attention of all the more recent workers in the State. 



» MannscHpt received by the Secretary of the Geological Society February 8, 1915. 

 *r,eol. Surv. Ohio, (ieol., vol. 2, p. 01. 

 =■ Ibid., p. 212, Geology of Lorain County. 



(205) 



