As a result of recent surface work in the Guadalupe Mountains and concurrent subsurface work by many petroleum geologists in New Mexico and W. Texas, it is apparent that the terms "Whitehorse, " "Chalk Bluff, " and "Bernal" in present use for this sequence of upper Guadalupian [Permian] shelf rocks are inappropriate or ill-defined. The Whitehorse formation was defined about 500 mi. NE. of the Guadalupe Mountains in Oklahoma and Kansas and applied to rocks of somewhat different stratigraphic sequence in New Mexico. The Chalk Bluff formation was not defined by a type section nor were precise stratigraphic limits designated, and it applied only to the evaporite facies. Although Bernal is well defined and is a mappable unit at the type locality, it includes only the lower part of the total upper Guadalupian sequence, Because of the inadequacy of the terms "Whitehorse, " "Chalk Bluff, " and "Bernal, " the new term "Artesia group" is hereby proposed to replace these names. The Artesia group extends from the top of the Tansill Formation down to the base of the Grayburg Formation and includes the Tansill, Yates, Seven Rivers, Queen, and Grayburg formations. It is a rock-stratigraphic unit, as are all formations of the group, and includes carbonate, evaporite, and clastic facies. For convenience, a reference well is designated in the subsurface in which the group has a thickness of 1710 ft. The Artesia group is a readily traceable unit in the Permian basin. It has been traced into N.-central New Mexico, western Texas, and southwestern Oklahoma, where it has been correlated with equivalent units.