1 9^> 



Cincinnati Society of Natural History. 



ver salts y var. elegantula, Strophomena hanoverensis^ Leptcena rhomboidalis, 

 Atrypa marginalis, var. multistriata, common, Orf/iis calltgramma, the 

 same form as that found at Hanover, Clathropora frondasa^ good speci- 

 mens, Rhinopora verrucosa^ Hemitrypa ulrichi, Phylloporina angulata, 

 Heliolites subtitbulatus, Favosites venustus, Favosites favosus, and Halysites 

 catenulatus . 



This is the most northern appearance of rock lithologically re- 

 sembling the Clinton from Hanover Indiana. 



e. Derbyshire Falls. — About half a mile south of Chris Mead's 

 quarry. The Clinton is here at least 90 inches thick. Beneath the 

 Clinton is plenty of bluish clayey shaly rock, wearing away more 

 rapidly than the Clinton and forming a deep fall. A more picturesque 

 fall lies about a quarter of a mile towards the northeast. 



Inside of a few miles the Clinton has increased from 8 to 90 

 inches. Towards the north the Clinton not only thickens to 135 

 inches, but becomes siliceous and fine grained and sandy in texture. 

 Fourteen miles towards the south, at New Point, it again becomes 

 thinner, being reduced to 35 inches. Three miles farther south the 

 Clinton is hardly over a foot thick, and at Osgood it is again 28 inches 

 thick. At several places the thinning out of the Clinton is. to say the 

 least, phenomenal. The extension of the Clinton, east and west, is 

 so considerable in Franklin county, that it may be possible here to 

 find a solution for the great variation in thickness of this formation in 

 Indiana. It is not improbable that such a solution would include 

 interesting suggestions as to the history of this marine basin during 

 Middle Silurian times, possible land conditions, and questions of early 

 folds in strata now forming part of the Cincinnati anticlinal. 



39. New Point. — North of New Point about a mile, are numer- 

 ous quarries opened up in the Laurel formation (Dayton stone ) This 

 rock is much eroded at the top, and the chert debris from higher beds 

 have fallen down into the crevises and have been covered by gravel 

 and soil. There are no chert layers intercalated with the flagging at 

 this quarry. The rock is singularly free of chert in general although 

 several layers include nodules of chert in moderate quantities. The 

 Laurel bed, where not weathered, in the quarry, is firm and sound to 

 its very base. In fact in some cases the upper 6 inches of the brown 

 Clinton and the lower 6 inches of the white Laurel formation have 

 come out of the quarry as a single firm block. East of the quarry, 



