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



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points along the Troy pike, south of Shoup's quarry, the most 

 southern exposure being about 6 miles from Dayton. This is the 

 most southern exposure along the road. 



20. West Charlestown Falls — about half a mile southwest of the 

 hamlet of that name on the Dayton and Troy pike, about a mile and 

 a half south of Col. Woodward's farm. The Dayton limestone is here 

 well exposed in the stream bed above the falls. The limestone is 

 yellowish, much softer than the typical rock, apparently more argil- 

 laceous, and usually in layers not exceeding 3 or 4 inches in 

 thickness. It looks much like the Ludlow Falls quarry rock, but is 

 inferior in quality. The total exposure of the Clinton at this point 

 does not exceed 27 feet. 



At its base are 42 inches of a rather firm greenish blue argilla- 

 ceous rock, in thick massive courses, though readily splitting under 

 the hammer. This represents the Belfast bed. Beneath are 34 

 inches of similar bluish green rock, but more shaly, breaking up into 

 thinner courses. Next are 9 inches of a firm, hard, fine grained, 

 blue limestone. Then 24 inches of soft blue clayey shale, 8 inches of 

 hardened greenish argillaceous rock, 12 inches of softer clayey rock, 

 18 inches of a hardened greenish rock, and 16 inches of a hardened 

 shaly clay rock, green, mottled with reddish purple. 



20^ . John Cushwa's Farm. — South west of West Charlestown Falls, 

 on an east and west road, a little over a mile northeast of Tadmor station 

 on the D. & M. Railroad is a roadside exposure, in front of the house 

 occupied by John Cushwa. The Clinton is exposed at the top of the 

 hill, its base being about 82 feet above the level of Tadmor station. 

 The rock is pink or reddish, and contains numerous crinoid stems. 

 The following fossils were found here : Illcenus ambiguus, Orthoceras 

 (Spyroceras) spyroceroides . There were two specimens of this species 

 of Orthoceras. One of them was 38 mm. broad; about 9 transverse 

 striations were found in a length of 6.5 mm. and 11 longitudinal 

 striations in a length of 6 mm. In a second larger, specimen, 6 

 transverse striations were found in a length of 6.3 mm. The longitu- 

 dinal striations were also present. Flatyceras (Platystoma) ntagarense, 

 the small Clinton form, Orthis fausta, Orthis e/ega/ttu/a, Rhynchonella 

 scobina, the small form, Ptilodiciya lanceolata var. americana, with the 

 lateral margins not waved, owing perhaps to the moderate size of the 



