CONCRETE-THOMPSON MAMMOTH SITE REDUX

Of several hundred mammoth finds from the greater Georgia-Puget Lowlands of southwest British Columbia and northwest Washington, no site or find has suffered as much at the hands of scholars as the Concrete-Thompson Mammoth Site. Barton (1999) inadvertently misrepresented the geography of the site by reporting it as situated above and overlooking the Sauk River. Riedel (2007) then compounded this error, in an otherwise excellent examination of the site geology, when he renamed the site as the “Mastodon Section”, suggesting the presence there of a family and genus of vertebrates not found at the site. Riedel further complicated the issue by basing his subsequent palaeoenvironmental analysis of the site on his belief in the presence of mastodon at the site, thereby falsely constructing a palaeoenvironmental interpretation unsuitable for the species actually recovered at the site. The purpose of this contribution is to address these published errors and to restore the credibility of the site and find. For the record, the Concrete-Thompson mammoth was discovered in 1979 on the hill slope directly above the Concrete-Sauk Valley Road, above the south bank and overlooking the Skagit River (contra Barton 1999), southeast of Concrete, Washington. The site/find was previously named by Barton (1999) for its proximity to the town of Concrete and for the site discoverers, Shawn and Bill Thompson. The find included several small pieces of highly fragmented cranium, portions of 2 tusks, and 2 complete upper sixth molars (left and right, LM⁶ and RM⁶) of a Columbian mammoth (Mammuthus columbi) (Barton 1999, fig.2). The diagnosis of these elements as “mammoth” remains valid, and no evidence of mastodon (contra Riedel 2007) was ever found at the site. Riedel argues that mastodons [browsers] preferred “spruce swamps and pine parkland”, and that given the presence of mastodon at the site such environments must have existed nearby. Riedel's palaeoenvironmental reconstruction for this site is no longer supported by the data from the site itself. Since the vertebrate in question at the Concrete-Thompson site was a Columbian mammoth, more typically classified as a grass and herb loving grazer (Barton 1998), and not a mastodon as Riedel would have it, Riedel's palaeoenvironmental reconstruction for this site is now negated and overturned.