Examination of Fossilized Turtle Remains from the Early Cretaceous (Albian) Willow Tank Formation, Clark County, Nevada
Johnson, Michael R.
MetadataShow full item record
The Willow Tank Formation in the Valley of Fire State Park, Clark County, Nevada provides an excellent opportunity to study North American terrestrial fauna of the Albian Age of the Early Cretaceous. The Early Cretaceous has not been studied as extensively as the Late Cretaceous, and no such study on terrestrial fauna has been conducted in Nevada. We excavated a turtle possessing pustule ornamentation from the site. First we brushed away surrounding rock and dust, and then covered the specimen with a protective plaster jacket for transportation back to Montana State University - Bozeman. Preparation of the specimen involved carefully removing bone fragments from their rock matrix, cleaning them with a dental pick, and then reassembling them with glue. The examination of reconstructed fossil fragments determined one to be a costal plate belonging to Naomichelys speciosa. I could not identify other bone fragments beyond belonging to the shell of the same Naomichelys individual. Presence of this turtle in the Willow Tank Formation suggests a relationship between this formation and the Cloverly Formation of Montana and Wyoming, the Paluxy Formation of Texas, and the Cedar Mountain Formation of Utah, all of which are interpreted as having been deposited in foreland basin ecosystems. As additional specimens gathered from the Willow Tank Formation are prepared and examined, we expect that they will comprise a faunal assemblage consistent with foreland basins.