Pg. E7-E8, pls. 1, 2. Willis Ranch Member of Word Formation. Word Formation restricted by removal of Road Canyon Member and establishing it as Road Canyon Formation. The three limestone members of the Word are herein named (ascending) China Tank, Willis Ranch, and Apple [Appel] Ranch. The Willis Ranch is the "Third Limestone" member of King (Univ. Texas Bull. 3038, 1931). At type section consists of (ascending) light-gray oolitic limestone, 218 feet; brown calcareous sandstone, 10 feet; gray limestone containing fossils and several seams of small quartz pebbles, 11 feet; and oolitic gray limestone in thin ledges, 69 feet. Member extends along south side of Road Canyon, where it makes large patches on dip slope. Curves northward and arcs under Gilliland Canyon, emerging on west side of that canyon where it has been mistakenly mapped as basal limestone member in the Word. Willis Ranch Member was not assigned a number on King's map, although it was identified as the "First Limestone" on plate 7 (P.B. King, 1931). However, the limestone on the west side of Gilliland Canyon now proves to be a continuation of the Willis Ranch Member, identified by its close lithic and faunal similarity to that member on the east side of the canyon where it is the "Third Limestone" member of King and King (IN P.B. King, 1931). Member terminates in southwest corner of mouth of southward extension of Gilliland Canyon. In vicinity of Old Word Ranch, member becomes dolomitic and merges with the undifferentiated mass of Word Formation. Age is Early Permian (Guadalupian).
Type section: near eastern entrance to Road Canyon, 1 mi southwest of the Old Willis Ranch site in west-central quadrant of Hess Canyon quadrangle, Glass Mountains, Brewster Co., western TX. (This is loc. 243 of R.E. King, 1931, Univ. Texas Bull., no. 3042, p. 136.)

Source: US geologic names lexicon (USGS Bull. 1350, p. 831).