Abstract

A sinkhole locality in the Wasatch Plateau has yielded Utah's first record of the American mastodon. At nearly 3,000 m this fossil-bearing site denotes the highest elevation yet reported for Mammut americanum, and demonstrates that mountainous terrain was not a barrier to dispersals. A presumably preferred habitat of spruce-fir open forests, similar to that in the area today, was present during the time of the mastodons reported here. Two incomplete individuals of M. americanum are the only fossils that were found in the sinkhole. Entrapment appears to have been the cause of death. Since the record of M. americanum in western North America is sparse, the present find has added significance in providing more information about the nature of this animal. A possible association of a recovered spear point fragment near the fossils indicates the possibility that man and mastodon were contemporaneous here. Three independent datings were run on mastodon bone. Two based on carbon-14 yielded dates of 7,090 ± 200 yr B.P. and 7,590 ± 100 yr B.P., while the third, using the racemization process, indicated an age of less than 10,000 yr B.P.