Tyrannosaurus rex from the McRae Formation (Lancian, Upper Cretaceous), Elephant Butte reservoir, Sierra County, New Mexico
— David D. Gillette, Donald L. Wolberg, and Adrian P. Hunt

In April 1983, D. Staton and J. LaPoint of Las Cruces, New Mexico, discovered a large jaw and other fossil material on the east side of Elephant Butte Reservoir. This material is referred to Tyrannosaurus rex Osborn on the basis of morphology and direct comparison to casts of the type specimen. The Staton- LaPoint locality lies within purple and maroon shales of the Hall Lake Member of the McRae Formation, probably several meters above the Hall Lake—Jose Creek contact now submerged beneath the waters of the reservoir. The fossil material consists of a nearly complete left dentary, and incomplete articular, a right  prearticular, incomplete isolated teeth, and one nearly complete chevron. The presence of T. rex in the McRae Formation, taken together with data developed elsewhere, supports a Lancian age assignment of these rocks.