The Rogers Gap Fauna of Central Kentucky • 119 



resembling Hehertella parksensis and Rafinesquina winchester- 

 ensis occur associated with Platystrophia colbieusis, Cyclonema 

 varicosum-cincinnatense, and a form resembling Orthorhynchula, 

 but with the cardinal margin not well preserved, all within six feet 

 of the base of the Clitainbonites horizon. 



Farther southward there appears to have been a fault, and at 

 the first switch north of the tunnel, south of Riverside, Trinucleus 

 occurs a short distance above track level. 



D. Cincinnati eastward to Ivor and Carnestown. 



Traces of the Rogers Gap fauna are found also along the Ohio 

 River, at various points east of Cincinnati — including Brent, Nine- 

 mile creek, and Ivor. Here its horizon is below the strata ex- 

 posed at West Covington, opposite Cincinnati, and above strata 

 regarded as equivalent to the Millersburg or Orthorhynchula divi- 

 sion of the Cynthiana formation. 



At West Covington, a coarse-grained crinoidal limestone layer, 

 two feet thick, occurred fifty feet above former low water, before 

 the dam was built below Cincinnati. Immediately above this cri- 

 noidal limestone belongs the Fulton or Triarthrus clay shale, well 

 exposed at various localities east of Cincinnati. This Fulton layer 

 forms the base of the Eden formation. 



Immediately below the crinoidal layer, at West Covington, for 

 a distance of about 25 feet, limestone is frequently interbedded 

 with clay shale for a vertical distance of 25 feet. The underlying 

 strata are chiefly shaly and form the Bromley member of the Cyn- 

 thiana formation. The overlying strata, in which interbedded lime- 

 stones are frequent, form the upper and best exposed part of the 

 Point Pleasant member, as exposed at the type locality, twenty 

 miles southeast of Cincinnati. 



About half a mile west of Brent, a short distance east of the 

 old waterworks station, directly north of Fort Thomas, I once 

 found Eridorthis in layers of rock near the river level, immedi- 

 ately over clayey strata in which argillaceous nodules were rather 

 common. At present this horizon is covered by water, owing to 



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