First used; intent to name not stated, and no type locality designated. Area of report is Lake Valley region, Sierra Co, NM in Orogrande basin. Is uppermost unit of the clastic series at Lake Valley, and differs very materially from all other terranes in being a gray, compact, massively bedded lime-rock of distinctly coralline character, yet exhibiting but few well-preserved organic remains. The fossils thus far found in this upper limestone suggest strongly the fauna of the "Upper Burlington" and "Lower Keokuk" limestones of the Mississippi Valley. The formation has an exposed thickness of about 50 ft. Overlies Lake Valley limestone; underlies Tertiary rocks. Age is Carboniferous ("Upper Burlington" and "Lower Keokuk"). Cross sections, geologic section.

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