372 The Ohio Journal of Science [Vol. XIX, No. 7, 



occur either in the 2-foot clay shale which overlies the typical 

 Upper or Blue Cliff rock, or in the immediately underlying parts 

 of the Upper or Blue Cliff rock, within 5 feet of the base of the 

 overlying clay shale. This clay shale is referred to in the 

 accompanying pages as the Holophragma zone, but Holophragma 

 ranges downward into the underlying Upper or Blue Cliff rock. 

 At the exposure immediately north of Crooked creek, on the 

 east side of the pike from Locust Grove to Sinking Springs, 

 at highest road level, exposures occur which are regarded as 

 stratigraphically equivalent to the top of the Upper or Blue 

 Cliff rock, as exposed at Hillsboro. 



It should be emphasized that in these lists are included 

 only those fossils occurring in the lower part of the Bisher 

 member and in the upper part of the Lilley member. The 

 fauna of the intermediate strata has not been well worked out. 



The Bisher member includes all of the Lower or West 

 Union Cliff of Orton. The Lilley member includes the massive 

 limestone layers which form the typical Upper or Blue Cliff 

 of Orton. The intermediate blue shale or soapstone was 

 included by Orton in the basal part of his Upper ot Blue Cliff 

 formation. In the vicinity of Hillsboro it is practically unfos- 

 siliferous. Such few fossils as may be identified in this inter- 

 mediate horizon appear to belong to the lower or Bisher fauna 

 rather than to the upper or Lilley fauna. The highest strata 

 exposed in the southeastern part of West Union may correspond 

 to these upper more shaly members. Such fossils as they 

 contain appear more nearly related to the Bisher fauna than 

 to the Lilley fauna. For the present, therefore, the base of the 

 Lilley member in the Hillsboro section, is drawn at the base of 

 the bluish, apparently argillaceous limestone which lies imme- 

 diately beneath the clay shale containing Holophragma calceo- 

 hides in abundance. At the Zink or Corporation quarry this 

 limestone has a thickness of 14 feet, and at the Trimble quarry 

 its thickness is nearer 21 feet. Beneath this more massive 

 limestone occurs a thinner-bedded, more or less laminated, and 

 frequently cherty limestone, with few fossils, beneath which 

 occurs the blue shale or soapstone mentioned before. No trace 

 of the characteristic Lilley fauna has been found so far in the 

 cherty limestone layers which occur beneath the more massive, 

 blue, apparently argillaceous limestone, and, therefore, the 

 base of the more massive blue limestone is regarded as forming 

 the base of the Lilley member. 



