Triassic rocks crop out in parts of the High Plains, the Glass Mountains
of Trans-Pecos Texas, and parts of Pecos, Crockett, Upton, Reagan, and
Glasscock and other west Texas counties. These are predominantly
nonmarine rocks consisting of conglomerates, sandstones, shales, and
some gypsum beds.
Triassic fossils are almost exclusively vertebrates, although some
poorly preserved plant and invertebrate remains have been reported.
Fossil vertebrates of the Texas Triassic include phytosaurs (Pl. 42),
crocodiles, amphibians, and fish.