[2] The formation consists of highly fossiliferous nodular argillaceous (clay-rich) limestone at its base and in its upper portion, with shale dominating the middle section and interbedding with the limestone towards the top of the formation.

[2] The formation is interpreted as an outer shelf formation that later experienced shallowing and deposition of limestone in an inner shelf environment subject to storm influence, then deepened again to deposit shale with some storm layers.

Trigonia emery Conrad, Helicocryptus mexicanus Bose, and Turritella granulata Sowerby var.

[1] The formation is highly fossiliferous, with some beds consisting almost entirely of fossils of the oyster Texigryphaea washitaensis.

[2] The beds making up the formation were first described by E. Bose in 1906 as subdivision 5 of his stratigraphic section.