SEDIMENTOLOGICAL AND TRACE FOSSIL EVIDENCE, ENVIRONMENTS OF DEPOSITION OF THE MEIGS MEMBER, COOSAWHATCHIE FM., GEORGIA

The coastal plain of Georgia is host to a wide variety of Miocene strata that have been assigned to the Coosawhatchie Formation. The five members of the Coosawhatchie differ greatly in their sedimentological and stratigraphic characteristics, but they are all acknowledged to be of marine, marginal marine, or freshwater origin. The general lack of fossils of any kind has lead to a poor understanding of the origin of much of Coosawhatchie, which is one of the most visible and widespread units on the Georgia coastal plain. We have found abundant, well-preserved burrows of thallasinoid shrimp (ichnogenus Ophiomorpha) and heart urchins (ichnogenus Scolicia) in the Meigs Member of the Cossawhatchie Fm. where it is exposed near Middleground, Bulloch County, Georgia. Therefore, the sediments are interpreted to have accumulated in near-shore environments of normal salinity.