Pg. 27 (table 2), 70 (fig. 7), 71-72. Del Cuerto formation of Keller group. Term proposed for rocks in lower part of Keller group (new) between top of Story formation (new) and base of Moya formation (new). At type locality, formation is 81 feet thick and composed of irregularly bedded to nodular limestone, highly arkosic sandstone, limestone conglomerate, and gray and red shale. In other areas, formation generally is more highly clastic and thicker. Fossiliferous (gastropods, brachiopods, corals, fusulinids). Age is Late Pennsylvanian (Virgil).
Type locality: northeast side of Oscura Mountains, in NE/4 sec. 31, T. 5 S., R. 6 E., and west-central part of sec. 32, Socorro Co., central NM. Named from Del Cuerto Spring on east slope of Oscura Mountains, about 3 mi east of Oscura Peak.

Source: US geologic names lexicon (USGS Bull. 1200, p. 1079-1080); supplemental information from GNU records (USGS DDS-6; Denver GNULEX).