The San Pedro Zacapa quadrangle lies along the valley of the Río Ulúa, just southwest of Lago de Yojoa in west-central Honduras. Most of the area lies within the sierras of northern Central America; volcanic ranges and ...

Carboniferous sedimentary rocks in eastern San Saba County and western Lampasas County are composed of an assemblage of lithosomes now assigned to the Houy, Chappel, Barnett, Marble Falls, Smithwick, and Strawn formations. ...