|Name||Mina Grande Formation|
|Geologic age||Permian; Guadalupe Series|
Sedimentary > Carbonate > Limestone (Bed)
|Comments||Limestone, hard massive, dolomitic, reefy, surface rough and hackly with brecciated appearance, gray to yellowish brown; serves as chief silver, lead and minor gold host rock (Presidio deposit) in Shafter district; also host of mineralization at Red Hills Cu-Mo porphyry system in Presidio Co.; thickness up to 400 ft in Shafter district, 25 ft in Upper Cibolo Basin, missing in many places due to pre-Cretaceous erosion.|
Bureau of Economic Geology, 1979, Emory Peak--Presidio Sheet, Geologic Atlas of Texas, University of Texas at Austin.
Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000.