It preserves fossils dating back to the late Devonian period.

It overlies the Sly Gap Formation and underlies the Lake Valley Limestone.

[2] The formation is thought to correlate with the lower Percha Shale.

[3] The formation was first defined by Frank V. Stevenson in 1945 for exposures at Rhodes Canyon in the San Andres Mountains.

Souraf also designed a new Salinas Peak Member and changed the spelling of Thoroughgood to Thurgood.