Mundy Breccia and Castner Limestone, undivided (TXpCAmc;0)

State	Texas
Name	Mundy Breccia and Castner Limestone, undivided
Geologic age	preCambrian-Proterozoic
Original map label	pCmc
Primary rock type	limestone
Secondary rock type	basalt
Other rock types	hornfels; conglomerate; dolostone (dolomite); diabase
Lithologic constituents	Major Sedimentary > Carbonate (Bed)Castner Limestone includes hornfels, conglomerate, dolomite, and diabase and is mostly light gray, green, and blue limestone, fine to coarse grained, lt. gray chert lenses, thin bedded, irreg. bedded in upper one-third; metamorphic minerals such as serpe Minor Metamorphic > Granoblastic > Hornfels (Hornfels)hornfels present in the upper third of the Castner Limestone, thus is ranked a minor part of the whole map unit (Mundy Breccia and Castner Limestone, undivided). Hornfels very fine grained, dark gray, in many thin beds, laminated and contains a few beds Incidental Sedimentary > Carbonate (Bed)Dolomite in the basal exposed beds of the Castner Limestone in the Franklin Mtns. The dolomite is white to light gray, one bed contains algal structures Tectonite > CataclastiteThe Mundy Breccia randomly oriented, black basalt boulders, angular to slightly rounded, in matrix of dark gray mudstone. thickness about 90 ft, as much as 250 ft maximum.
Map references	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
Unit references	Bureau of Economic Geology, 1968, Van Horn-El Paso Sheet, Geologic Atlas of Texas: Bureau of Economic Geology, The University of Texas at Austin, scale 1:250,000. Harbour,R.L., 1960, American Association of Petroleum Geologists Bulletin v. 44, no. 11, p. 1788-1790.
Geographic coverage	El Paso