Named as upper of two formations of Keller group (new) of Virgil series for Moya Spring on east slope of Oscura Mountains, about 8 mi south of north end of range. Type locality is section measured mainly in NE1/4 sec 31, T5S, R6E, and extends a short distance into west-central part of sec 32, in north end of Oscura Mountains, Socorro Co, NM in Orogrande basin. Overlies Del Cuerto formation (new) of Keller; underlies Bruton formation of Fresnal group (both new). At type is composed of 51 ft of light-gray, massive to massively bedded and irregularly bedded limestone with a few thin beds of irregularly bedded to nodular limestone. Sandstones and shales are interbedded with the limestones in Los Pinos Mountains, Abo Canyon section, in Mocking Bird Gap section, and at least as far south along Rio Grande Valley as Mud Springs Mountains, Sierra Co. Upper limestone of the formation forms the top of the prominent rock terrace on northeast side of canyon. Most limestones that form the east dip-slopes throughout Oscura Mountains are referable to Moya. Fossiliferous; fauna is large and varied. At type, pelecypods and bellerophon gastropods are especially abundant in upper limestone member, fusulinid foraminifers are common throughout the section. All fusulinids so far found at type are genus TRITICITES. Is Pennsylvanian (Virgil) in age.

Source: GNU records (USGS DDS-6; Denver GNULEX).