Melinda Hurlbut, Dixie State University
Physical Sciences
A newly discovered plant fossil locality in the Chinle Formation (Upper Triassic) in Washington County broadens the distribution of known Late Triassic plant fossil localities to include southwestern Utah. Previously reported plant localities in the Chinle Formation are known from southeastern Utah, Arizona, New Mexico, and equivalent strata from the Dockum Group in Texas. The majority of the known plant fossil localities are from higher stratigraphic units of the Chinle Formation. However, the new Washington County locality is from the older, basal unit, the Shinarump Member. The plant fossils identified from the new locality include fronds of the fern Phlebopteris sp., fertile leaves of the fern Cynepteris sp., and leaves of the bennettitalean Zamites sp. Undetermined species of conifers are represented by a partial branch and a three- dimensionally preserved cone containing well preserved seeds. The diversity of species found at the Washington County plant fossil locality correlates with other known floral assemblages from the Chinle Formation, suggesting general homogeneity of Chinle Formation floras. These plant fossil assemblages support interpretations of basal Chinle Formation paleoclimates as humid and warm.