REVIEWS 77 



Prior to Prosser's work Ohio stood well in the quantity and quality 

 of the work done by its state surveys. However, owing to the intricate 

 nature of many of the formations and the difficulty of properly inter- 

 preting them, much remained to be accomplished. Prosser's work has 

 thrown much additional light on these formations, as the tables of forma- 

 tions show. The revised list of formations is as follows: Alluvium and 

 Glacial, Dunkard formation, Monongahela formation, Conemaugh for- 

 mation, Allegheny formation, Pottsville formation, Maxville limestone, 

 Logan formation. Black Hand formation Cuyahoga formation, Sunbury 

 shale, Berea grit, Bedford shale, Ohio shale (consisting of the Cleve- 

 land shale, the Chagrin formation, and the Huron shale), Olentangy 

 shale, Delaware limestone, Columbus hmestone, Monroe formation 

 (consisting of the Lucas Limestone, the Sylvania sandstone, and the 

 Tymochtee member?), "Niagara group" (consisting of the Hillsboro 

 sandstone, the Cedarville limestone, the Springfield limestone, the West 

 Union limestone, and the Osgood beds), Clinton limestone, Belfast bed, 

 Saluda bed (which is regarded as probably forming the upper part of 

 the Richmond), Richmond formation, Eden shale, and Trenton lime- 

 stone. 



The priority, synonomy, correlation, and application of these names 

 are fully discussed in the Bulletin. J. W. B. 



