The Brazil Formation was named in 1902 for the city of Brazil, located in Clay County, Indiana. It originally included rocks between the bottom of the Petersburg Coal and the top of the Mansfield Sandstone. In 1922, a new survey resulted in restrictions to include only rocks between the Lower Block Coal Member and what was at the time called Coal II. In 1976, it was amended again to include rocks between the upper part of Minshall Coal Member and the lower part of Lower Block Coal Member.
The formation is made up of shale, sandstone, clay, and coal. Thickness is measured between 40 and 90 feet.[1]
The formation was named by E. R. Cumings to refer to the exposed rocks found near Staunton, Clay County. Later surveys resulted in the inclusion of the Perth Limestone Member into the Staunton Formation, having previously belonged to the Brazil Formation.
The Staunton Formation is made up of sandstone and shale (75 to 150 feet), and coalbeds (up to 8).[3]
References
↑Hutchison, Harold C. "Brazil Formation". Indiana Geological and Water Survey. University of Indiana Bloomington. Retrieved 11 October 2021.
