ABSTRACT

The Claron Formation in southwestern Utah is well exposed and accessible along Sweetwater Creek, west of the Table Cliff Plateau. The formation locally is divided into eight informal lithologic units. Mollusks, charophytes, and ostracods are common in all of the local units except one. Vertebrates have been recovered from one unit and include crocodilians, fish, anurans, lizards, and mammals. The vertebrate specimens were transported fluvially and size sorted so that only very small specimens (~1 mm) are present in the sample. Mammalian taxa include the marsupials Peradectes sp., cf. P. chesteri, and cf. Peratherium sp.; indeterminant insectivores; and the rodents Knightomys reginensis and K. minor. The rodents indicate an early Eocene age (Wasatchian North American Land Mammal Age), and the marsupials are consistent with that interpretation. Among the specimens are two taxa (a symmetrodont and an eomyid rodent Protadjidaumo) that are likely not part of the contemporaneous fauna and may be the result of screen contamination, or possibly, in the case of the heavily abraded symmetrodont specimen, reworking. Fossil bone is rare in the Claron Formation whereas eggshell is relatively common suggesting that vertebrates may have been diverse but diagenesis has limited their record.

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