Named as upper unit of Upper Cretaceous Allison Member of Menefee Formation of Mesaverde Group for La Vida Mission Indian School, San Juan Co, NM in San Juan basin. Type section designated in northeast corner sec 31, T22N, R13W at top of promontory at 6,200 ft with offsets to abandoned road at 6,160 ft to top of southern tip, White Rock Mesa, sec 30. Composed of mudstone, olive-gray and dark brown; olive-gray siltstone; dark gray shale; gray, fine-grained sandstone. Upper half to two-thirds of unit contains lenticular coal beds of which most are more than 1 ft thick. Is 232 ft thick at type section. Overlies Juans Lake Beds of Allison; underlies Cliff House Sandstone. Deposited in a fluvial, distributary and interdistributary environment. Petrified wood and ironstone concretions common.

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