TAXONOMIC ANALYSIS OF THE EARLY EOCENE MAMMALIAN FAUNA OF THE BIG HORN BASIN

The Willwood Formation of the Big Horn Basin, Wyoming, has yielded a large collection of early Eocene mammalian fauna, recovered during the years of 2002 – 2004 by the Big Horn Basin Collection Team at Indiana State Museum (ISM) Site One. Preliminary paleoenvironmental analysis of the area based upon past geologic work suggests the paleolandscape consisted of a meandering river/floodplain system. The purpose of this study is to provide a more complete paleoecological picture through the preliminary analysis of the taxonomic composition and abundance of the early Eocene mammalian remains recovered from the approximately ten square mile area designated ISM site 1. The fauna examined here consists of approximately 200 cranial specimens primarily surface collected. The specimens were identified to at least the order level and taxonomic abundances were calculated using both minimum number of individuals (MNI) and number of identified specimens (NISP). The taphonomy of the specimens is also taken into consideration. Measures of taxonomic abundance will be evaluated for significance using SPSS. The ultimate goal of this analysis is to compliment preliminary paleoenvironmental descriptions, and provide a more complete paleoecological study of ISM site one.