USGS Visual Identifier

GEOLEX

Summary of Citation: Poison Canyon

Publication:
Hills, R.C., 1888, The recently discovered Tertiary beds of the
   Huerfano River basin, Colorado: Colorado Scientific Society
   Proceedings, v. 3, pt. 1, p. 148-164
Usage in Publication:
Poison Canyon conglomerates, series

Modifications: Geologic Province: Dominant Lithology:
 First used
  Las Vegas-Raton basin
  Conglomerate
Sandstone
Clay
Marl

Summary:
First published use as Poison Canyon conglomerates (p. 151) and as Poison Canyon series (p. 152). [Definition and areal extent not clearly stated.] Section 7,000 to 8,000 ft thick measured down Poison Canyon and across Muddy Creek to Promontory Bluffs, Huerfano Co, CO in the Las Vegas-Raton basin. Section divided into: lower 3,500 to 4,500 ft thick yellowish sandstone and conglomerate with occasional yellow clay or marl beds; middle 1,500 ft of red, white, brown or variegated sandstone alternating with red and yellow sandy clay and marl; upper 2,000 ft of red and yellow sandy clay and marl that is shaly at some localities alternating with yellow, white, gray, and green sand. [The lower beds may be Hills' Huerfano beds.] Unconformably overlies the Laramie [formation] and Colorado [formation]. The middle beds are well exposed along Poison Canyon near its mouth. Fossils: turtle bones, Coryphodon bones [location of fossils not stated]. Sketch map shows location of rocks of Eocene age. Assigned to the early Tertiary, Eocene.
Summary of Citation: Poison Canyon

Publication:
Hills, R.C., 1890, Orographic and structural features of Rocky
   Mountain geology: Colorado Scientific Society Proceedings,
   v. 3, pt. 3, p. 362-458
Usage in Publication:
Poison Canyon beds

Modifications: Geologic Province: Dominant Lithology:
 Revised
  Las Vegas-Raton basin
  

Summary:
Name restricted in the Las Vegas-Raton basin to the middle and lower divisions of the measured section on Muddy Creek, Huerfano Co, CO in the Las Vegas-Raton basin. The upper division is reassigned to the Huerfano. Error made by author in his original notes. Eocene age.