Contadero Formation

The Contadero Formation is a geologic formation in the San Andres Mountains of New Mexico. It preserves fossils dating back to the late Devonian period.

Description

The formation consists of limestone, shale, and siltstone. The total thickness is at the type section. It overlies the Sly Gap Formation and underlies the Lake Valley Limestone.
The formation is divided into three members : the Salinas Peak Member, the Thurgood Member, and the Rhodes Canyon Member.
The formation is thought to correlate with the lower Percha Shale.

Fossils

The formation contains brachiopods and horn corals, with 20 genera and 24 species of brachiopods identified. These are characteristic of the late Frasnian.

History of investigation

The formation was first defined by Frank V. Stevenson in 1945 for exposures at Rhodes Canyon in the San Andres Mountains. While revising New Mexico Devonian stratigraphy in 1984, Souraf assigned all Devonian beds above the Sly Gap Formation to the Conadero Formation, including beds previously assigned to the Thoroughgood and Rhodes Canyon Formations, which were reduced to member rank within the Conadero Formation. Souraf also designed a new Salinas Peak Member and changed the spelling of Thoroughgood to Thurgood.