ii Taphonomic Comparison of Two Horizons From Don ’ s Gooseberry Pit , Black Hills , SD

Pit caves contain large samples of terrestrial micro-vertebrate specimens that accumulate during periods of surface erosion. The fossil record for vertebrates is riddled with biases that often mask paleoecological and biogeographical information. Taphonomic biases need to be realized and accounted for before making any interpretations on these faunal accumulations. Here we present a study analyzing the effect of trap effectiveness in pit caves on the preservation and representation of fossil classes as a function of pit depth. Micro-vertebrate remains from two excavation horizons of different depths from Don’s Gooseberry Pit in the Black Hills of South Dakota were analyzed. The results of this study show that for shallow traps there is a significant bias with depth in the variety and types of organisms trapped in deposits of this nature. This bias is shown to be dominantly a result of preferential accumulation of smaller organisms, particularly rodents, in the shallower excavation level. The findings also suggest that post-depositional survivorship of specimens is diminished at greater depth, which may be a result of overburden from burial.