PALEONTOLOGIC ANALYSIS OF THE WACCAMAW FORMATION AT NEILS EDDY LANDING, ACME, NORTH CAROLINA

A series of extinction events affected Western Atlantic mollusks during the Plio-Pleistocene. Several geologic formations along the North American East Coast capture these extinction events. Among them is the fossiliferous Waccamaw Formation. As part of a Research Experience for Undergraduates program, paleontological analyses were conducted for the Waccamaw Formation at Neils Eddy Landing, Acme, NC, a locality along the Cape Fear River. Four bulk samples were collected from the locality. The samples were sieved through a 5-millimeter mesh and bivalves with intact beaks and gastropods with intact apices were sorted and identified to genus level. The study included 1,489 bivalve specimens in 55 different genera, and 126 gastropod individuals in 16 different genera. Based on rarefaction analysis, the level of bivalve diversity exceeds that of past samples from the Waccamaw Formation, with diversity comparable to that of the older Duplin Formation. Of the bivalves, 1,417 (95.2%) individuals and 41 genera are suspension feeders; 747 are infaunal siphonate, 260 are infaunal asiphonate, and 766 are epifaunal. The high percentage of suspension feeders indicates that there was not a productivity decrease during the extinction phase captured at Neils Eddy Landing. The level of gastropod diversity is consistent with other samples from the Waccamaw Formation, potentially indicating a different response to the Plio-Pleistocene extinctions from the bivalves. Of the 126 individuals, 80 (63.5%) are suspension feeders, consisting of the genera Turritella and Crepidula. Thirty individuals (23.8%) are predatory carnivores, consisting of 11 genera. Overall results indicate a level of diversity comparable to that of the stratigraphically lower, pre-extinction Duplin Formation.