The fossils described in this paper substantiate the Permian age of the Rustler formation. The Rustler fauna is largely molluscan and has a Whitehorse aspect. Four species of the Rustler fauna are similar to species from Russian and Indian faunas, suggesting possible correlations with Upper Permian rocks. Environments have had more influence on the fauna than has geologic age, giving the Rustler fauna a striking resemblance to faunas of older Permian rocks which occupied similar biotopes. The Rustler fauna is large and varied, containing 35 species of invertebrates. Because of the fragmentary condition of the fossils, many species are uncertainly identified.