Cincinnati Society of A r atural History. 



exposed during the blasting of a drainage trench. In the Clinton 

 were found Cyclonema />i/ix, Orthis fissiplicata, Orthis elegantuUiy Pachy- 

 dictya {Rhinodictya ?) rudis, Rhinopora verrucosa, Callopora magnipora, 

 Heliolites subtu-bulatus, Favosites favosus, Striatopora flexuosa, Halysites 

 catenulatus, Syringopora ( Drymopora) fascicularis^ Ptychophyllum ipomcea, 

 a fine specimen 4 inches broad and 1^ inches high, Diphyphyllum 

 C(BSpitosum 1 and Chonophyllum niagarense 



28. Lmikburgh — twenty miles a little north of west of Dayton, 

 on Twin Creek. About half a mile south of Lewisburgh, on the east 

 side of the pike, on the land of Mr. James Stetler, is a ditch leading 

 from a culvert on the pike directly eastward to a rocky descent which 

 gives rise to a waterfall in wet weather. In the ditch the Dayton 

 limestone is exposed. Its color is yellowish and it does not look as 

 though it would wear well. Below it lies the Clinton, almost 13 feet 

 thick. It is a limestone, coarsely granular, more or less crinoidal, 

 but otherwise with but few fossils. The upper part is stained more 

 or less brownish by iron compounds, and the lower part is nearly pure 

 white in color. Luckily a good pygidium of Illtznus daytonensis was 

 found about 8 inches above the base of the Clinton, thus corroborating 

 its recognition by iithological methods. This was very necessary 

 since the Clinton at its base is immediately underlaid by a 3 inch 

 course of hard bluish limestone with Orthis occidentalis and many 

 branching Lower Silurian bryozoa. This makes it necessary to 

 draw the dividing line between the Upper and Lower Silurian forma- 

 tions between two immediately adjacent limestone beds. The result 

 is that the Belfast bed is seen to be totally absent here. One to three 

 inches at the base of the Clinton limestone are more or less streaked 

 with thin greenish tinged shaly layers, but this need not be the Belfast 

 bed. Below the 3 inch layer of Lower Silurian limestone mentioned 

 above, are about 3 feet, of which the upper part can be seen to be 

 blue clayey shale, and the lower part, though not exposed, is probably 

 the same. Beneath are 4 inches of a hard fine-grained limestone. 

 Then comes an interval in which no rock was found, there being no 

 exposure. Without instruments it was impossible to measure this 

 interval accurately, but 11 or 12 feet was assumed as fairly accurate. 

 Below this came 19 inches of a hard, blue, very fine-grained limestone, 

 whose upper surface was marked with glacial scratches running 

 approximately north and south. Below this were 25 inches of blue 



