An Account of the Middle Silurian Rocks of Ohio and Indiana. 1 8 1 



12 feet of material, blue shale at the top, but apparently more 

 clayey below. How far beneath this level the regular limestone 

 layers of the Cincinnati group are found is not known at present with 

 certainty. The 26 feet below the Belfast bed are all here included 

 in the Cincinnati group. 



23. Piqua. — Going from Troy northward on the electric cars to 

 Piqua, Statler's quarry is found 1^ miles south of Piqua. Here the 

 Dayton limestone is quarried. Half a mile south of Piqua the Clinton 

 is exposed along the side of the track. At this point were found 

 like mis daytonensis, a glabella, Phanopora magna, Heliolites subtubulatus ', 

 Halxsites calaialalus, and Ptychophyllwn iponuea. On the eastern side of 

 the bridge at Piqua was exposed the Clinton with Strophomena palenta, 

 and typical specimens of Pachydictya bifurcata. The thickness of the 

 Clinton was at least 20 feet. Its total thickness was not certainly 

 known. Going down the eastern side of the Miami river, to a point 

 opposite Statler's quarry, at Huffman and Horn's quarry, the Dayton 

 limestone is quarried. It contains not infrequently fossil remains at 

 the surfaces along the bedding planes. The Clinton is exposed below, 

 and shows very few fossils near the top. 



24. Ludlow Falls — one mile west of the Stillwater, and two and 

 a half miles north of West Milton. Here the Clinton is overlaid by 

 stone corresponding to the Dayton limestone. The courses are 

 however only 4 to 6 inches thick, and there is a greater thickness to 

 the total section of this variety of limestone than farther south or south- 

 east. There are at least 6 feet of rock of fair quality; it graduates 

 upwards into the stone which near Dayton is included in the Niagara 

 shale. Elsewhere the transition from the Dayton limestone into the 

 Niagara shale series, even when the name shale is a misnomer, is 

 more sudden. There is no marl or clay intervening between the 

 Dayton limestone and the Clinton. The Clinton is at least 16 feet 

 thick at the falls, and to this 4 to 6 feet must be added in order to 

 bring the section up to the level of the junction of the Clinton and 

 the Dayton limestone as shown in the cut near the railroad depot. 

 This would give the Clinton a total thickness of 20 to 22 feet. The 

 Clinton here is not very fossiliferous, though quite a number of forms 

 were found in the upper Clinton, when the cut along the railroad, 

 mentioned above, was made. Underlying the Clinton are two and 

 a third feet of blue argillaceous but quite firm stone, in layers usually 



