NPS Paleontology Research Abstract Volume


THE PLEISTOCENE DUNG BLANKET OF BECHAN CAVE, UTAH

Owen K. Davis and Paul S. Martin
Laboratory of Paleoenvironmental Studies
Department of Geosciences
University of Arizona
Tucson, AZ 85721

Larry Agenbroad and Jim I. Mead
Quaternary Studies Program
Northern Arizona University
Flagstaff, AZ 86011

Boluses of dung rich in graminoid stems dropped by a large herbivore and comparable in size and content to African elephant (Loxodonta) dung were discovered recently in Bechan Cave, southeastern Utah. Two boluses were radiocarbon dated at 11,670 and 12,900 yr B.P., respectively. They are embedded in a 225 cubic meter dung blanket along with fecal remains and hair of ground sloths, artiodactyls, and small mammals. While no diagnostic bones of mammoth were recovered, the deposit yielded long coarse hair attributed to mammoth.
The unusual discovery supports the previous report by Hansen (in Jennings, 1980) of mammoth dung at Cowboy Cave, Utah. Both deposits constitute major finds for paleoecologists and are the most impressive discovery of their kind since the discovery in the 1930's of dry caves yielding ground sloth dung in Nevada, Arizona, New Mexico, and west Texas. The Bechan Cave deposit accumulated during an interval of vegetation change when blue spruce and water birch declined, oak became more abundant, and the regional vegetation was sagebrush steppe. Blue spruce and water birch currently occupy higher elevations in southern, Utah. Megaherbivore occupation of Bechan Cave evidently ended hundreds of years before mammoth and ground sloth (Nothrotheriops) extinction in the region, ca. 11,000 yr B.P.





LATE PLEISTOCENE VERTEBRATES FROM BECHAN CAVE, UTAH

Jim Mead and Larry Agenbroad
Department of Geology
Northern Arizona University
Flagstaff, AZ 86011

Anthony Stuart
Norwich Museum
Norwich, England

Typically the vertebrate paleoecologist is left with only skeletal remains to provide a reconstruction of the various animals, their diet, and their associated biotic community. The hyperarid climate of the Colorado Plateau provides an unusual preservational environment where little organic decay has occurred since deposition during the Wisconsin Glacial. The Pleistocene organic layer in Bechan Cave contains +300 cubic meters of predominantly plant remains and herbivore dung. This is a unique deposit in that it contains a great quantity of dry-preserved animal remains. Megaherbivore species identified from dung include: Mammathus sp., Euceratherium collinum, Nothrotheriops shastensis, Bison sp., and cf. Oreamnos harringtoni. Only two skeletal remains of a large species have been recovered from the excavations (Euceratherium: LM/2, fragment of a metapodial). Microfaunal studies of Pleistocene deposits are rare on the Colorado Plateau outside of the Grand Canyon. Fine sieving of the excavated deposits has permitted the recovery of an associated microfauna. Identified species from Bechan Cave include: Scaphiopus intermontanus, S. cf. bombifrons, Pituophis melanoleucus, Crotalus cf. viridis, a grouse-sized bird, Brachylagus idahoensis, Marmota flaviventris, Spermophilus sp., Thomomys sp., Lagurus curtatus, Microtus sp., and Neotoma cinerea.




Back to Table of Contents

United States Department of the Interior, National Park Service