272 EDITORIAL 



rocks of the Hamilton formation. As these were partially 

 exhausted new quarries were opened to the westward in rocks 

 of the Sherburne formation, and later farther west in the Catskill 

 Mountain region in rocks of the Catskill formation. At the 

 present time the greater part of the "bluestone" is obtained 

 from the Sherburne and Catskill formations ; but to the trade it 

 is all generally known and sold as the " Hudson River bluestone." 

 The name Bedford shale was given by Dr. Newberry to the 

 geologic unit which is well exposed at Bedford village, southeast 

 of Cleveland. The formation varies in thickness from fifty to 

 one hundred feet ; is sharply defined lithologically with its base 

 resting on top of the black Ohio shale while its top is marked 

 by the base of the Berea grit. In distribution it extends from 

 eastern Ohio across the northern part of the state to Huron 

 county, and thence south across the state to the Ohio River and 

 into Kentucky. At a few localities in northern Ohio, especially 

 near Cleveland, the shale includes from fifteen to twenty feet of 

 valuable sandstone which is used considerably in that city for 

 flagging and building stone. The Bedford shale of Ohio is as 

 thick a formation as the Bedford limestone of Indiana; litholog- 

 ically it is more sharply limited ; it has, apparently, as great 

 areal distribution ; as the name of a definite geologic division it 

 has appeared in geological literature for a longer time and to a 

 much greater extent ; but it does not contain as valuable 

 economic deposits of building stone. 



Charles S. Prosser. 



May 2, 1901. 



