It preserves fossils dating back to the Visean Age of the Mississippian.

[1] The formation consists mostly of dense carboniferous silty limestone containing considerable chert.

The base of the formation is a few inches of shale and carboniferous quartz sandstone, followed by a few feet of yellow to brown sandy siltstone and a few feet of carboniferous limestone composed almost entirely of crinoid fragments.

[1] The formation contains intraformational submarine erosional surfaces but relatively little slumping, indicating deposition on a deeply submerged stable basin floor.

[4] The basal sandstone contains numerous plant fossils and the lower limestone is almost entirely crinoid fragments.