Mammals of the Ardis Local Fauna 



unconformably overlies the Santee Limestone as the "Cooper Marl" 

 of early to late Oligocene age. A more recent survey by Ward et al. 

 (1979) recognizes three members of the "Cooper Marl" (Cooper 

 Formation), the Ashley (Oligocene), the Harleyville (late Eocene), and 

 the Parkers Ferry (late Eocene). The Parkers Ferry and Ashley members 

 were absent at the Ardis fossil locality. Harris and Zullo (1991) refer 

 to the Harleyville member as the Harleyville Formation, and we follow 

 that practice in this paper. Since Sanders' (1974) study, fossil vertebrates 

 of presumed late Pleistocene origin have been collected by workman 

 and hobby collectors from several areas of the quarry, although no 

 stratigraphic assignment could be determined for these fossils. Most 

 were collected from spoil piles of unknown origin. 



In April 1991, during a periodic visit to the quarry, the senior 

 author, accompanied by Mr. Vance McCollum, a hobby collector, 

 discovered a newly-mined area in the southeastern wall of the quarry 

 which contained a dense concentration of late Pleistocene terrestrial 

 vertebrate fossils. Giant Cement, in anticipation of further mining 

 operations, had used a dragline to remove overburden from the 

 underlying Santee Limestone. This was done in a single strip which 

 formed a trench at a right angle in the southernmost corner of the 

 pit. This tract of freshly mined earth had a maximum length of about 

 150 m, a width of 10 m, and a depth of 4 m. Fossils were initially 

 collected from a single row of spoil piles dumped adjacent to the area 

 from which they were mined. We determined that the fossil material 

 came from a series of localized, sediment-filled cavities formed in the 

 underlying Harleyville Formation and Santee Limestone. Groundwater 

 had preferentially dissolved away the upper portions of the Santee 

 Limestone, so that many of the solution cavities contacted the overlying, 

 clay-rich Harleyville Formation. This resulted in the occasional collapse 

 of the Harleyville Formation, opening several of the cavities to the 

 surface. 



The diameter of the solution cavities varied from a few centimeters 

 to a maximum diameter of nearly 2.0 m, with many of the cavities 

 interconnected. The solution cavities reached a maximum depth below 

 the Harleyville Formation of about 4 m. The majority of the cavities 

 were infilled with clastic sediment from the surface. The sediment is 

 well stratified and ranges in size from clay to small pebbles. Multiple 

 fining-upward sequences within the cavity-filling deposits indicate episodic 

 sedimentation, perhaps corresponding to flood events within a nearby 

 fluvial system. The undisturbed clay layers within the cavity-filling 

 and the narrow interconnecting nature of the cavities indicate that 

 the entire deposition probably occurred over a relatively short time 



