Pg. 1717, 1718, 1719, 1722; West Texas Geol. Soc., 1940, West Texas Geol. Soc. Gdbk. Fall field trip, Sept. 1940, p. 7, 14, fig. 2. Ocotillo silt member of Tansill formation of Whitehorse group. Consists of sand marl, buff-gray magnesium limestone, and silt in upper part of formation. Thickness 13.5 feet at type locality of Tansill [beds VIII to X]. [Age is Late Permian (Guadalupe).]
Named from Ocotillo Hills, prominent topographic feature northwest of Carlsbad, [Carlsbad West 7.5-min quadrangle, Eddy Co.], southeastern NM. Member traceable over long distance on surface and in subsurface.
Named from Ocotillo Hills, prominent topographic feature northwest of Carlsbad, [Carlsbad West 7.5-min quadrangle, Eddy Co.], southeastern NM.
Type locality (of Tansill Formation): on Carlsbad-Artesia Highway (U.S. 285), 3.7 mi from Eddy County Courthouse in Carlsbad, in W/2 sec. 26, T. 21 S., R. 26 E., of NM Principal Meridian, [Carlsbad West 7.5-min quadrangle], Eddy Co., southeastern NM.

Source: US geologic names lexicon (USGS Bull. 1200, p. 2801).