New Mexico Geological Society Annual Spring Meeting — Abstracts

The youngest Triassic strata in the Hagan basin of north-central New Mexico pertain to the Correo Sandstone Bed of the Petrified forest Member of the Chinle Formation. The Correo Sandstone Bed is 5.5 to 24m crossbedded, quartzose sandstone and lithic- and limestone-cobble conglomerate exposed along an arcuate outcrop belt that extends from sec. 12, T13N, R5E on the north to the vicinity of Puertecito
(sec. 15, T12N, R6E) on the south. Across this outcrop belt, the Correo forms a prominent cliff above reddish brown mudstone of the petrified forest member of the Chinle Formation and below the medial silty member of the Jurassic Entrada Sandstone. Fossil vertebrates from the Correo Sandstone Bed are fragmentary remains of phytosaurs and metoposaurid labyrinthodonts as well as coprolites, some of which contain ganoid fish scales. These fossils indicate Late Triassic age and occur primarily in conglomerates, especially in the NE1/4 NW1/4, sec. 13, T13N, R5E and the SW1/4 NW1/4,sec. 10, T12N, R6E.

Recognition of the Correo Sandstone Bed in the Hagan basin extends its distribution about 80 km to the northeast of its type locality (and supposed easternmost outcrop) at Mesa Gigante (T9N,R3W), Valencia County, This extension is based on similarities in lithology, stratigraphic position and fossils of the type outcrops in the Hagan basin.