79 



clay shales are interbedded with fine-grained siliceous 

 limestones, some of which weather to a brownish rock 

 resembling fine-grained sandstone. This rock frequently 

 contains an abundant pelecypod fauna, including: — 



Clay Cliffs, Manitoulin island, showing Lorraine exposures in the background and 

 Richmond in the distance. 



Byssonychia radiata (Hall ) 

 Cleidophorus planulatus Conrad. 

 Ctenodonta pectunculoides Hall. 

 Lydrodesma poststriatum (Emmons). 

 Modiolopsis concentrica Hall and Whitfield. 

 Whiteavesia pholadiformis (Hall). 



These pelecypods are associated at least at one 

 horizon, with Diplographts angnstifolius mut. vespertinus 

 of the middle Lorraine of New York. 



In Ohio, Whiteavesia pholadiformis and Mediolopsis 

 concentrica come in at the base of the Waynesville member 



