FIRST OCCURRENCE OF THE PECCARY PLATYGONUS COMPRESSUS IN THE PACIFIC NORTHWEST

The RULO site, located in the southern Palouse Hills 25 km north of Walla Walla, Washington, is characterized by an accumulation of loess, diamict related to pre-late Pleistocene glacial flood events, multiple carbonate paleosols and at least three tephras. The stratigraphy of the RULO site comprises four distinct depositional sequences separated by local unconformities with a total thickness of about 19 meters. The section is cut by at least 2 generations of clastic dikes. The basal Sequence 1 is a 1.5 meter thick accumulation of quartz-mica bearing sand with large scale cross stratification, a poorly sorted diamict that contains extra-basinal (non-basalt) clasts, and a paleosol, resting on Columbia River Basalt. The basal contact is not exposed. Overlying that are three unconformity-bounded sequences of moderately sorted mostly massive fine-grained sediment, each of which is several meters thick. There are at least 13 carbonate paleosols in the section. Preserved within these sequences are three tephra horizons. The lower tephra occurs in Sequence 2; its origin is unknown. The upper two tephras occur in Sequence 3 and are geochemically strongly similar to tephra from Long Valley, California and Newberry Volcano in Oregon (ca. 220 ka). Of particular significance at RULO is the occurrence of a diverse vertebrate fossil fauna excavated primarily from Sequence 1 and the lower part of Sequence 2. The fauna includes partial remains of a tortoise, several rodent species; a rabbit, a horse, a bison, a canid and at least two individuals of the peccary Platygonus compressus. P. compressus is known from late Pleistocene deposits from Florida to the Yukon, but this is the first documented occurrence in the Pacific Northwest of the United States. The fauna is mixed and fragmental, suggesting post-mortem transport and concentration. The tephra ages and physical stratigraphy suggest that the fauna is of Irvingtonian age.