The fossil collections are from both the richly fossiliferous Golden Horn Limestone Lentil and from other strata in the formation. The collections were studied by R.E. Grant in consultation with E.L. Yochelson and J.T. Dutro, Jr. (written commun., 1966). According to Grant,

"the fauna is not differentiated by rock type, at least as concerns genera that might be useful for correlation. Only a few genera of brachiopods are present, and they are the ones normally found in the Arctic Permian. Correlation must depend more on the absence of certain elements than on presence of common Arctic genera. The brachiopod fauna contains Permian elements, but none that definitely indicates a Late Permian age. Therefore, Early Permian is suggested by default. Yochelson examined snails in samples 62Apr-11D (USGS 22379-PC, which he identified as species of Straparollus (Euomphalus). They are not sufficiently well preserved for specific identification, but they seem to resemble S. (E.) cornudanus (Shumard) of Wolfcampian age more closely than S. (E.) of late Leonard and Word age. This tentative opinion suppots the essentially negative evidence of the brachiopods that the collections are Early Permian."

Grant's faunal list of the collections follow. All collections are from the McCarthy C-4 quadrangle, and their localitions are keyed alphabetically to plate 1. A few collections that appear to contain similar fauna were made in the B-4 quadrangle.

p. Q25: On the basis of the paleontologic evidence, the Hasen Creek Formation and the Golden Horn Limestone Lentil are considered to be Early Permian.