The Rogers Gap Fauna of Central Kentucky 141 



ture specimens. Compared with the type of Tetranota ohsoleta, 

 these Rogers Gap specimens are more flattened dorsally and the 

 umbiHcus appears relatively larger. In the vicinity of Cincinnati, 

 Nickles lists Tetranota bidorsata from the strata below the Fulton 

 layer, while Tetranota obsoleta is listed only from the lower third 

 or Economy division of the Eden. However, since Tetranota obso- 

 leta was described by Ulrich as ranging from the Stones River 

 through the Black River and Trenton to the Eden, the reference 

 of the Rogers Gap form to the latter species is probably correct. 

 Bellerophon globiilaris, Miller and Faber, is probably a Tetranota. 

 Tetranota obsoleta is figured on plate 65 of the Geology of Alinne- 

 sota, volume 3. 



39 — Cyrtoiites retrorsus. Ulrich — A form referred to this 

 species was found at 58.8 miles from Ludlow. It ranges from the 

 Trenton into the lower third or Economy division of the Eden. 

 Cyrtoiites retrorsus is figured on plate 63 of the Geology of Minne- 

 sota, volume 3. 



40 — Bellerophon rogersensis, sp. nov. (Plate II, Figs. 4A, B, 

 C) — A species of Bellerophon is very common at the railroad cut 

 59.1 miles from Ludlow. It occurs also at 60.3, 59.8, 59.7, 59.5, 

 58.3, and 54.8. It is very imperfectly known, but probably repre- 

 sents a new species. It is closely related to the group of shells 

 typified by Bellerophon reetin'ns, Ulrich, in which the aperture is 

 only moderately expanded laterally, producing an elongate, rather 

 than laterally widened outline of shell, when viewed from the dor- 

 sal side of the aperture. In the Rogers Gap species the aperture 

 appears even less expanded laterally than in the upper Maysville 

 species cited above. The lower margin of the lip is turned back so 

 as to cross the central part of the umbilicus and thus practically 

 close the latter. The shell itself is not preserved. The carina 

 on the casts of the interior is low and rounded, often becoming 

 quite indistinct on the last half of the last volution. The speci- 

 mens often appear laterally compressed, but this is regarded as 

 due to their state of preservation in a more or less argillaceous 

 rock. 



37 



