82 GEOLOGICAL REPORT. "127 



In Noxubee and Kemper, however, there is one stratum peculiarly rich in 

 fossils, and containing them chiefly as nuclei much harder than the mass of the 

 rock and therefore in the best condition to be washed out. unharmed, by rains 

 and streams. The mass of this stratum is rather more clayey, and softer, than 

 is usually the ease — as may be perceived at an extensive exposure on a hillside 

 E. of Wahalak Creek, where a stratum of gray calcareous clay, about 1T> feet 

 thick, is over and underlaid by the common Rotten Limestone. This clay 

 Stratum contains a fauna rather different from that usually found in the latter, 

 approaching somewhat, in character, to those of the gray clay overlying the 

 limestone of the Eipley (!roup(«[137) ; and the same as collected by L. Harper 

 and myself, in 1855, on the bald prairies S. W. of Macon. It is characterized by 

 the 1 comparative scarcity of the usual oysters, (except Ostrea falcata which is 

 very abundant), the absence of • ostata and the presence of numerous 



univalves. Natica petrosa, Niatiea sp., Pyrula trochiformis, P. Bickardsoni, 

 and several other species of Pyrula and 1% sp., several Bostella- 



rice, Voluta cancellaria, Cerithium Scalaria Sillimanni, Actaeon 



(Bullopsis ?) 2 sp. This great prevalence of univalves is very unusual, as is 

 that of the bivalves whose nuclei are abundant here, viz : CrassateUa, 2 sp.. 

 Cucullaea vulgaris, C.ungula, Nucula, 2sp., Cardium sp., Lucinas'p, ■ 

 Idliiifi, Astarti ■ .' sp., ClavagelUdeae, Hamulus Onyx; and others. Besides the 

 shells already mentioned, Placuna scabra, Plieatula urh Anomia sp., 



Ostrea pleumosa, cretacea ?, and two other small undetermined sp. : Gryphaea 

 conroexa, Pitclieri, Wxogyra costata, Icktyosarculites comutus, I. lo 

 quadrangularis, Nautilus Delcayi, Samites torquatus, Turbinolia sp., teeth 

 and vertebrae of Mosasaurus, teeth of Otodus appendiculatus, Corax apfiendicula- 

 ius and Carcharias, were found here. 



The abundance and variety of fossils occurring i;i this locality, and no less 

 the great prevalence of univalves, are very unusual in the Rotten Limestone of 

 Mississippi. Unfortunately, with the exception of the oysters, little more than 

 the interior cast of the fossils is usually preserved in this stratum, rendering 

 identification difficult. In Alabama, according to Tuomey, this group of fossils 

 is rather more commonly found. In the collection of the Alabama Survey at 

 Tuscaloosa, there are several nuclei from the Rotten Limestone, of a Cardium 

 closely resembling, if not identical with, Cardium Spiflmahi, Cox. It is 

 observable at first sight, that the facies of the fauna of this stratum approaches 

 very closely to that of the uppermost clay stratum of the Ripley Group (1T133, 

 137); although a close examination may demonstrate the species to b 

 lative only, and not identical. 



127. The Pwidiolites (7/. Aimesii and undidatus), though a very striking 

 palreontologieal feature, are by no means common, and being a conspicuous 

 fossil, those specimens which had been washed out of the rock on the bald 

 prairies, early found their way to cabinets and private mantels — which is the 

 only source from which I have as yet obtained them. The Ichtyosarc 

 likewise, are rare. 



