Pg. 11-12, 36 (table 6). Espinal grit [unranked] in Joserita member of Lowell formation of Bisbee group. Division 8c, coarse partly conglomeratic grit with imperfectly rounded and subangular pebbles of limestone, quartzite, chert, arkose, and sandstone. Large inclusions of underlying yellow dolomite. Southward grades into sandstone, arenaceous shale, and limestone. Thickness 4 feet. Underlies Corta sandstone (new) and overlies unnamed dolomite; both in Joserita member. Fossils. Age is Early Cretaceous (Aptian); DUFRENOYA DUFRENOYI standard ammonite zone.
[Occurs in the Ninety One Hills area, local name for hills in secs. 14 and 23, T. 24 S., R. 24 E., immediately north of International border in vicinity of International Monument No. 91, southeast of Bisbee Junction on Southern Pacific RR, Bisbee 15-min quadrangle, Cochise Co., southeastern AZ. Area includes type locality and standard section of Lowell Formation.]

Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 1286).