Pg. 18 (fig. 8), 29-31, pl. 1. Totavi Lentil of Puye Conglomerate. Poorly consolidated conglomerate composed of material ranging from fine-grained sand to boulders more than 1 foot in diameter. Thickness about 53 feet at type locality. Nonconformable with underlying undifferentiated unit of Santa Fe Group at some places and disconformable at other places. In northeastern part of area is overlain conformably by fanglomerate member of the Puye. At northwest tip of Sagebrush Flats, is overlain unconformably by arkosic sedimentary rocks of upper tongue of undifferentiated unit of Santa Fe Group. Overlain and interfingers with basaltic rocks of Chino Mesa in White Rock Canyon. To west, interfingers in subsurface with quartz latite flows of Tschicoma Formation. Age is late Pliocene.
Type locality: quarry just north of Totavi, in NW/4 SE/4 SE/4 sec. 15, T. 19 N., R. 7 E., Los Alamos area, north-central NM. Base not exposed in quarry. Named for community of Totavi in eastern part of area.

Source: US geologic names lexicon (USGS Bull. 1350, p. 769).

Totavi Lentil not specifically mentioned in this report except to imply acceptance as a part of Puye Conglomerate of Griggs (redefined in this report from Conglomerate to Formation). Age of Puye changed from late Pliocene? to middle to late Pliocene in this report--therefore presumably age of Totavi refined as well. Totavi is not shown on stratigraphic chart. Study area is San Juan basin.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Totavi Lentil of Puye Formation. Basalt sample from Totavi Lentil of Puye Formation, in Cerros del Rio volcanic field, White Rock quadrangle, Sandoval County, New Mexico, yielded a K-Ar age of 2.6 +/-0.4 Ma (whole-rock); provides minimum age for ancestral Rio Grande.

Source: Modified from GNU records (USGS DDS-6; Denver GNULEX).

As classified in previous USGS reports, Santa Fe Group in its type region (Espanola basin, north-central NM in San Juan and Estancia basins) is middle? Miocene to Pleistocene? in age. Tesuque Formation is Miocene to Pliocene, and is unconformably overlain by Ancha Formation near southeastern margin of Espanola basin, and by Puye Formation to west. In this report, new radiometric ages provide more precise dating for Tesuque, Puye, and Ancha Formations of Santa Fe Group. Ancha has been assigned a Pliocene or Pleistocene age--fission-track age of 2.7 +/-0.4 m.y. was obtained from zircons in pumice 15 m from top of Ancha type locality. Puye is Pliocene--zircon fission-track age of 2.9 +/-0.5 m.y. was obtained from a pumice bed directly overlying Totavi Lentil of Puye, 8 km north of type locality of Ancha (Santa Fe Co, NM in Estancia basin). These ages support the correlation of Puye and Ancha Formations and establish a minimum age for the Rio Grande [River] (Totavi Lentil of Puye) in Espanola basin.

Source: GNU records (USGS DDS-6; Denver GNULEX).