Schwimmer.fm Page 31 Monday, June 18, 2012 11:54 AM SOUTHEASTERN GEOLOGY V. 49, No. 1, June 2012, p. 31-41 AN APHELASPIS ZONE (UPPER CAMBRIAN, PAIBIAN) TRILOBITE FAUNULE IN THE CENTRAL CONASAUGA RIVER VALLEY, NORTH GEORGIA, USA DAVID R. SCHWIMMER1 WILLIAM M. MONTANTE2 1Department of Chemistry & Geology Columbus State University, 4225 University Avenue, Columbus, Georgia 31907, USA <
[email protected]> 2Marsh & McLennan, Inc., 3560 Lenox Road, Suite 2400, Atlanta, Georgia 30326, USA <
[email protected]> ABSTRACT shelf-to-basin break, which is interpreted to be east of the Alabama Promontory and in Middle and Upper Cambrian strata the Tennessee Embayment. The preserva- (Cambrian Series 3 and Furongian) in the tion of abundant aphelaspine specimens by southernmost Appalachians (Tennessee to bioimmuration events may have been the re- Alabama) comprise the Conasauga Forma- sult of mudflows down the shelf-to-basin tion or Group. Heretofore, the youngest re- slope. ported Conasauga beds in the Valley and Ridge Province of Georgia were of the late INTRODUCTION Middle Cambrian (Series 3: Drumian) Bo- laspidella Zone, located on the western state Trilobites and associated biota from Middle boundary in the valley of the Coosa River. Cambrian beds of the Conasauga Formation in Two new localities sited eastward in the Co- northwestern Georgia have been described by nasauga River Valley, yield a diagnostic suite Walcott, 1916a, 1916b; Butts, 1926; Resser, of trilobites from the Upper Cambrian 1938; Palmer, 1962; Schwimmer, 1989; Aphelaspis Zone. Very abundant, Schwimmer and Montante, 2007. These fossils polymeroid trilobites at the primary locality and deposits come from exposures within the are referable to Aphelaspis brachyphasis, valley of the Coosa River, in Floyd County, which is a species known previously in west- Georgia, and adjoining Cherokee County, Ala- ern North America.