|Name||Eocene volcanic rocks|
Igneous > Hypabyssal > Felsic-hypabyssal
Igneous > Volcanic > Felsic-volcanic
|Comments||igneous rocks mapped on Christmas Mt. on Emory Peak-Presidio Sheet (1979) Brewster Co., Big Bend Natl Park. Map description is given only as extrusive or intrusive igneous rocks of Tertiary age on that map. Petrography of sample coll. at locality no. 195 on Little Christmas Mt. (Maxwell and others, 1967, p. 218, Table 13)--Prophyritic quartz aegirine-augite trachyte. varies in composition approaches rhyolite.|
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.
|Counties||Brewster - Presidio - Reeves|