The Abstract from my Masters thesis
Comparison of Mammuthus primigenius and Mammuthus columbi

Three mammoth molars identified as Mammuthus primigenius were collected at San Antonio Estero in Marin County Northern California in 1923.   Subsequent finds of mammoth remains have yielded no other Mammutus primigenius specimens within Northern California, making the classification of this find questionable.

Two populations of North American mammoths, M. primigenius and M. columbi were statistically compared using an analysis of variance to determine differences in mean length, width, enamel thickness and number of enamel ridges.  Using the two compared populations of mammoths as a model, the measured characters of the questionable Marin “primigenius” was statistically compared to M. primigenius and M. columbi specimens.    Statistic similarities in mean enamel thickness and mean number of enamel ridges between the Marin “primigenius” fossils and Mammuthus columbi , along with geographic and stratigraphic correlations strongly suggest that the original 1923 identification is in need of revision, and that the Marin “primigenius” is actually a Mammuthus columbi.  This revision would be consistent with the currently accepted geographic and temporal range of M. columbi, and would not extend the range of M. primigenius into Northern California.

Publications
Davies, R.I., and Spittler, T.S., 1999,  Index to published landslide maps, California Coast Ranges, Monterey County and north for use in timber harvesting plan preparation on non-federal land, California Division on Mines and Geology Special Publication 120, 1999.

Wilen, J.E., Lancaster, J.,Allen, J., and Davies R.I. 2002,  Temporal Significance of Volcanic Ash, Petrified Wood, and Uplifted Fluvial Terrace Deposits in the Chileno and San Antonio Creek Drainages, Marin County, California, GSA Poster session, Denver Colorado.