- Usage in publication:
-
- San Miguel conglomerate*
- Modifications:
-
- Original reference
- Dominant lithology:
-
- Conglomerate
- AAPG geologic province:
-
- Paradox basin
- San Juan Mountains province
Summary:
Pg. 235-241. San Miguel conglomerate. Characteristically a coarse conglomerate, in which pebbles of many kinds are recognizable at a glance (granite, schists of various kinds, hard bluish quartzites, limestones, red sandstones, and some dense porphyritic eruptive rocks). Thickness 200 to 1,000 feet in Telluride district, [San Miguel, San Juan, and Ouray Counties], southwestern Colorado. Great unconformity at base. Rests on rocks of Colorado Cretaceous age. Conformably overlain by San Juan formation. Age is Eocene.
Typically exposed on north side of Miguel River, from Marshall Creek westward for several mi, Telluride district, southwestern CO.
[GNC remark (ca. 1936, US geologic names lexicon, USGS Bull. 896, p. 1916): Later replaced with Telluride conglomerate, because of prior use of San Miguel for a Cretaceous formation in Texas.]
Source: US geologic names lexicon (USGS Bull. 896, p. 1916).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).