The Cincinnatian Series and its Brachiopods. 23 



these fossils, which may be considered as characteristic of 

 the Eden as a whole, there are certain other fossils, which 

 are characteristic of one or more of its members. 



The members of the Eden are; lower or Economy (50 ft.), 

 middle or Southgate (120 ft.), and upper or McMicken 

 (60 ft.). These members are characterized by certain 

 Bryozoa:* the Economy by Aspidopora newberryi; the 

 Southgate by Batostoma jamesi; the McMicken by Deka- 

 yella ulrichi. Lithological distinctions between these divi- 

 sions are not clearly marked. The Eden is a formation of 

 much greater uniformity than any of the succeeding forma- 

 tions. 



Besides the typical bryozoan of each member, other 

 fossils which are easily recognized, but not as uniformly 

 present, ma}' be mentioned. In the Economy may be 

 found: Dalmanella emacerata, Leptaena rhomhoidalis gibbosa, 

 Pholidops ctncinnatiensis, Plectambonites plicatellus, and 

 Trinucleus concentricus. The Southgate contains a more 

 meager fauna than the Economy and is not sharplv differ- 

 entiated from the beds above or below it. Dalmanella 

 emacerata, Pholidops cincinnatiensis, and Trinucleus con- 

 centricus are here also, and Rafinesquina squamida, which 

 does not occur again below the Fairmount (see table, 

 Part II), is occasionally present. The McMicken contains 

 a rich bryozoan fauna, and but few representatives of the 

 other classes. 



Exposures of the Eden around Cincinnati are not com- 

 mon. On Elberon Ave. and on Straight St. are good ex- 

 posures of the higher beds; the lower strata are exposed 

 only in a few stream beds near the river level. 



About 210 to 220 feet above the base of the Eden is a 

 prominent horizon marked by two massive limestone strata 

 separated by about eight or ten feet of shale. The lower 

 limestone stratum is 5 to 8 inches thick, and contains few 



*Nickles: Jour. Gin. Soc. Nat. Hist., vol. 20, 1902, p. 69. 



