Named as lower member of Renova Formation (new) for creek in northern Madison Co, MT. Type section designated 1.25 mi southeast of Renova village along west-facing bluffs on east side of Jefferson River in NW1/4 NW1/4 sec 33, T1N, R4W to SW1/4 NW1/4 sec 28, T1N, R4W, Madison Co, MT, Montana folded belt province. Crops out over about 5 sq mi in north end of Tobacco Root Mountains, where occurs in light-colored, nearly white, dissected benchlands. Consists of alternating sequence of micritic and oolitic limestone, montmorillonite mudstone, vitric siltstone, vitric arenite, arkose, and minor conglomerate. Thickness estimated to exceed 1,700 ft and may be as thick as 3,500 ft. About equivalent age to Climbing Arrow Member of Renova. Unconformably overlies pre-basin (pre-Tertiary) rocks. Comformably underlies Dunbar Creek Member of Renova. Geologic map, correlation chart, cross sections, fossil list. Early Oligocene (Chadronian) age suggested from vertebrate fossils.

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