Pg. 18 (fig. 8), 58-59, pl. 1. Valles Rhyolite of Tewa Group. Domes of Valles Rhyolite exhibit zoning more or less parallel to outer surface. Where domes are only slightly eroded, the outer rind is jumble of blocky pumice and pumiceous glass that grades from white to light-gray to pale pink. Toward interior of this zone are local areas of obsidian. Glassy rind changes farther inward to slightly porous light-gray rhyolite. Rocks in deeply eroded parts of domes are light-gray and fine-grained rhyolite. Northernmost dome of Valles Rhyolite in Cerros de Trasquilar cuts Tschicoma Formation. Valles Rhyolite of western dome of the Cerros de los Posos cuts Cerro Toledo Rhyolite (new). Valles Rhyolite not in contact with Cerro Rubio Quartz Latite (new) or Bandelier Tuff at any place in east half of Valles Caldera. West of Los Alamos area, Valles Rhyolite was extruded through Tshirege Member (new) of Bandelier Tuff. Age is Pleistocene.
Type locality: rhyolite domes in Valles Caldera in west-central part of Los Alamos area, north-central NM.

Source: US geologic names lexicon (USGS Bull. 1350, p. 793).

Valles Rhyolite of Tewa Group. Divided into 6 members (ascending): Deer Canyon, Redondo Creek, Valle Grande, Battleship Rock, El Cajeta, and Banco Bonito. Age is Pleistocene. Adopted by the USGS.

Source: Changes in stratigraphic nomenclature, 1969 (USGS Bull. 1324-A, p. A14).

Pg. 24-25, geologic time scale (inside front cover). Valles Rhyolite. Samples from (ascending) Redondo Creek Member, Valle Grande Member, and Banco Bonito Member, in Jemez Mountains, Sandoval County, New Mexico, yielded fission-track ages from 0.78 +/-0.21 Ma to 0.13 +/-0.10 Ma (zircon). Ages calculated using decay constants of Steiger and Jager, 1977 (Earth Planet. Sci. Letters, v. 36, p. 359-362). [Quaternary, based on time scale of Berggren, 1972 (Lethaia, v. 5, no. 2, p. 195-215). See also entries under individual members.]

Source: Publication.