Named for exposures in the water gap of Johnson Gap. Type section measured 3 mi west of Torres, CO in sec 20, T34S, R69E, Las Animas Co in Las Vegas-Raton basin. Extends into adjoining NM. Consists of thin to thick beds of gray silty siliceous limestone conglomerate that contains pebbles and cobbles of gray, finely crystalline limestone. Conglomerate is interbedded with: gray, red, silty, siliceous limestone; red, siliceous, thin-bedded siltstone; green, gray and brown shale; and gray and red fine-grained quartzose sandstone. Is 90 ft thick at type; thickens south from a wedge-edge 2 mi north of Johnson Creek to about 110 ft in thickness at Gold Creek, NM. Recognized in subsurface. Rests unconformably on Sangre de Cristo formation; overlain unconformably by Entrada sandstone. Correlated with Dockum group. Formerly mapped as part of Sangre de Cristo formation. Assigned a Triassic? age.

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

Restricted stratigraphically to units 10 and 11 of the Johnson Gap type section or all post-Trujillo Formation Triassic rocks north of Naranjos, Mora Co, NM in the Las Vegas-Raton basin. Units 1-9 of the type are reassigned to Trujillo Formation. As restricted, is 15.4 to 84.9 m thick and dominantly gray-red, olive and green, sandy siltstone with lesser amounts of litharenite sandstone and intraformational conglomerate. Is equivalent to Redonda Formation south of Naranjos. Correlation chart. Cross sections. Identified in measured sections in Colfax Co at Rayado Creek, Uracca Creek, Cimarroncito, and Ricardo Creek. Of Late Triassic, Norian age.

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