An Account of the Middle Silurian Rocks of Ohio and Indiana. 



195 



dictya obesa, Rhinopora verrucosa, Heliolites subtiibulatus , Favosites favosus, 

 Cyathophyllum celator, var. daytonense, and a large specimen of Ptyc/10- 

 phyllum ipomoea. Under the Clinton was a layer of blue clay 2 1 inches 

 thick. Below this was a layer of coarsely granular Cincinnati lime- 

 stone, resembling the Clinton lithologically, 7 inches thick, and con- 

 taining Plectambonites sericea, Stroplwmena alternate:, also var. fracta, 

 Strophomena planumbona, Ort/iis occidentalis, and Orthis biforata, Lower 

 Silurian type. 



Above the Clinton is a soft brown stone, similar to the lowest 

 part of the Laurel bed at Ball's quarry near Longwood. There may 

 be about 6 feet of this soft rock. Above this occur about 3 feet of a 

 very hard, firm white rock, very much like the Dayton rock in Ohio. 

 These two kinds of rocks above the Clinton constitute the lower half 

 of the Laurel formation. Above these occurs a rapid alternation of 

 chert and stone over 6 feet in thickness forming a characteristic 

 exposure of the upper half of the Laurel formation. 



b. Henry Dice's quarry . — One mile south of Geyer's quarry. The 

 Clinton here was 24 inches thick. The exposure was otherwise simi- 

 lar to that at Geyer's quarry. 



c. Seegat's quarry. — One mile south of Dice's quarry. The Clinton 

 was here a reddish crinoidal limestone 33 inches thick. Beneath it 

 occurred 2^ inches of blue clayey shale, 2% inches of stone, 

 2]/ 2 inches of blue clayey shale, 2 Y / 2 inches of stone containing 

 Plectambonites sericea, Strophomena filitcxta, and Orthis occidentalis. 

 Beneath this were 2 feet of blue clayey shale. Farther down was a 

 considerable abundance of clayey shale. 



d. Chris Mead's Falls Quarry. — Haifa mile south of Seegar's quarry. 

 Here the Clinton was 90 inches thick. A large part had a crinoidal 

 character, but a portion had the appearance of the brownish Clinton 

 from Hanover, Indiana. Immediately below the Clinton was blue 

 clayey shale, containing loose typical Cincinnati Group fossils within 

 several inches of the Clinton. Above the Clinton was a brown, soft 

 rock, in thin courses, forming the basal portion of the Laurel forma- 

 tion (Dayton stone.) The middle and upper portion of the Laurel 

 bed with its intercalated cherty beds was well exposed in the quarry 

 near by. 



The Clinton at this point contained Ilhcnus daytonensis, glabella 

 and pygidium, Calymene vogdesi, large pygidium, Plectambonites trans- 



