The Cinci)inati(in Series and its Brachiopods. 29 



forminj; llic pix'iloniinatinj^^ ruck oi the division, is inter- 

 bedded with tliin hix'ers of shale. The base of the Liberty 

 is marked by the first a])])earance of Hehertella insculpta. 

 Strophoncma planunibona, from which the Liberty is called 

 the Strophonema zone, Rhynchotrema capax, Plectam- 

 bonites sericeus, Bythopora meeki and Rhombotrypa quadrata 

 are present in large numbers. The upper layers contain 

 fewer fossils, and in ])laces become argillaceous and are- 

 naceous. 



Saluda. — The Saluda division is even more markedly 

 argillaceous or arenaceous than the upper layers of the 

 Liberty. The typical exposure of this division is at Madison, 

 Indiana, where it is chiefly a sandy limestone, or calcareous 

 sandstone. Northward, it becomes more calcareous, and 

 coarse sediments are lacking. At Richmond, Indiana, it is 

 represented by only a few feet of massive limestone. On 

 the east side of the Cincinnati anticline, the Saluda is 

 chiefly a shale horizon. In the southern area of its outcrop 

 in Indiana, ripple marks and sun cracks are common in the 

 more shaly layers. Reef building corals, Tetradium minus 

 and Coliimnaria alveolata, are very abundant. Two coral 

 reefs are present, separated from each other by several feet 

 of argillaceous rock. In the southern portion of the area 

 both are composed of Columnaria. If these are traced 

 northward, the upper is seen to be replaced by Tetradium. 

 The Tetradium reef is much more persistent than the Co- 

 lumnaria reef, but is absent at Richmond, Ind. Both corals 

 become much less abundant in the northern part of the area. 

 At Madison, Ind., the Saluda is separated from the Silurian 

 by 20 feet of mottled limestone, which represents only the 

 lower portion of the Whitewater. Cumings^ interprets the 

 Saluda as a shore deposit related to the Whitewater and 

 Ellvhorn, which overlie the thin calcareous representative of 

 the Saluda in the more northern sections, as at Liberty and 

 Richmond, Indiana. Many authors consider the White- 



*S. planumbona (Halli. See Nickles: Am. Geol. xxxii, 1903, pp. 214-217. 

 tCumings: Ind. Dept. Geo). Nat. Res., 32nci Ann. Rep., 1907, p. 673. 



