THE CYNTHIANA, CATHEYS, AND LEIPERS 581 



sists in the strata which are assigned to the Leipers. There are not many 

 species which pass from the Catheys to the Leipers, but the faunas are 

 essentially alike, the younger being a derivative of the older, and in actual 

 field-work it is very difficult to distinguish the two. 



This is especially well illustrated in the section in the city of Nash- 

 ville. The highest strata, well exposed in a large quarry north of the 

 reservoir and at Fort Negley, on the summit of Saint Cloud hill, are 

 called Catheys by some and Leipers by others. And verily these beds 

 carry a mixed fauna. Large specimens of Orthorhynchula linneyi are 

 very common there, and a variety of Platystrophia ponderosa, much 

 larger than any of the specimens lower in the Catheys, is not infrequent. 

 On the other hand, large Isochilinse and Cyclonema varicosum proclaim 

 the Catheys, while Hebertella sinuata provides but indifferent evidence. 



There is, furthermore, no physical evidence so far brought forward 

 which indicates any interruption of sedimentation at the top of the 

 Catheys. The clearest statement on the part of one who believes that 

 there was a land interval between the Catheys and Leipers is that of 

 Ulrich. 11 



"In middle Tennessee, where the emergence at the close of the Trenton 

 continued through Utica and later stages of the Eden the elevation must 

 have been very broad and without marked local flexing. Erosion of the 

 Catheys prior to the submergence of the west and north flanks of the dome 

 by the late Cincinnatian or Leipers sea is indicated chiefly by the local 

 absence of some of the upper layers. There are no clastic deposits worth 

 mentioning at the contact of the Leipers and Catheys. The plainest feature 

 of the physical evidence of the hiatus between the two is the unquestionable 

 landward overlap of the Leipers. The most western exposures of the contact 

 contain a number of clearly distinguishable beds in the lower part of the 

 Leipers which are entirely absent in the Nashville hills ; and on the south 

 flank, as near Fayetteville, the Leipers is represented by only the uppermost 

 member, the lower Platystrophia bed." 



The evidence for the overlap mentioned is outlined in the Columbia 

 folio, and consists in the fact that different faunas were found in the 

 strata considered to be the base of the Leipers at different localities. 

 This does not seem t*o the writer at all sufficient to establish the case un- 

 less accompanied by a very detailed explanation of the distribution of 

 the various species. 



In place of the current opinion that Catheys and Leipers times are 

 separated by an interval during which the Eden of Kentucky and Ohio 

 were deposited, I wish to present the idea that this was a region of con- 



Bull. Geol. Soc. Am., vol. 22, 1911, p. 311. 



