Named for small community across Rio Grande east of Cerro de Cristo Rey. Divided into 4 units (1-4, ascending order). Type section lower part (units 1, 2)--NW/4 SW/4 NW/4 sec 15, T29S, R4E, Dona Ana Co, NM, Orogrande basin; type upper part (units 3, 4)--SE/4 SE/4 NE/4 sec 16, T29S, R4E, Dona Ana Co. Most extensive outcrops eastern and southern sides of Cerro de Cristo Rey intrusion, Dona Ana Co, NM and Chihuahua, MX. At type for lower part, unit 1 --45 ft thick consisting of medium-dark-gray shale; unit 2 --47 ft thick consisting of silty calcareous dark-gray shale with coarse sand and dark chert pebbles, corals, and bryozoans upper part. At type for upper part, unit 3 101.5 ft thick consisting of silty olive-gray shale with interbedded strata of fine sandstone, siltstone, some beds of silty limestone up to 30 cm thick with sole marks common; unit 4 8 ft thick consisting of fine-grained ferruginous sandstone beds up to 25 cm thick, interbedded with silty shale with lebenspuren and sole marks common. Conformably overlies Del Norte Formation (new); conformably underlies Muleros Formation (new). Geologic maps; cross sections; chart comparing nomenclature used in area. Equivalent to Bose's (1910, Inst. Geol. Mexico, Bol. 25) unit 4. May be correlative with Duck Creek Formation northeast TX. Fossils not abundant though do indicate Smeltertown lies near Fredericksburg Group-Washita Group boundary in TX. Early Cretaceous (late Albian, Comanchean) age.

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