- Usage in publication:
-
- Conquista clay member*
- Modifications:
-
- Original reference
- Adopted
- Dominant lithology:
-
- Clay
- AAPG geologic province:
-
- Gulf Coast basin
Summary:
Pg. 2626 (table 1), 2631. Conquista clay member of McElroy formation. Substituted for preempted Falls City shales (Ellisor, 1933, AAPG Bull., v. 17, no. 11). At type locality, consists of about 70 feet of pale-yellowish-brown to chocolate bentonitic clay. Overlies Dilworth sandstone member of McElroy; underlies Stones Switch sandstone member of Whitsett formation. Age is Eocene.
Type locality: bluff adjoining historic Conquista Crossing on San Antonio River, 3.75 mi southwest of Falls City, Karnes Co., south-central TX. This is the same type locality as Falls City shales.
Source: US geologic names lexicon (USGS Bull. 1200, p. 921).
- Usage in publication:
-
- Conquista Clay Member*
- Modifications:
-
- Revised
- Adopted
- AAPG geologic province:
-
- Gulf Coast basin
Summary:
Conquista Clay Member of †McElroy Formation (now abandoned) of Jackson Group reassigned as member of Whitsett Formation of Jackson Group. Overlies Dilworth Sandstone Member (reassigned from McElroy to Whitsett); underlies Deweesville Sandstone Member (new). Present in south-central Texas. Age is late Eocene. (Conquista Clay Member of Whitsett Formation of Jackson Group adopted by the USGS and Texas Geol. Survey.)
Source: Changes in stratigraphic nomenclature, 1972 (USGS Bull. 1394-A, p. A10-A11).
- Usage in publication:
-
- Conquista Clay Member
- Modifications:
-
- Areal extent
- AAPG geologic province:
-
- Gulf Coast basin
Summary:
Conquista Clay Member of Whitsett Formation. Clay and sandstone; clay, bentonitic, slightly carbonaceous, locally lignitic pale to medium yellowish brown, some marine megafossils; sandstone, fine-grained, lenticular. Thickness 50 feet. Underlies Deweesville Sandstone Member and overlies Dilworth Sandstone Member (both of Whitsett). Age is considered Eocene and Oligocene(?).
Not separately mapped. [Present in Karnes Co., southeastern TX.]
Source: Modified from GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Conquista Clay Member
- Modifications:
-
- Areal extent
- AAPG geologic province:
-
- Gulf Coast basin
Summary:
Conquista Clay Member of Whitsett Formation of Jackson Group. Clay, bentonitic, slightly carbonaceous, lignitic, chocolate to pale yellowish brown, locally concretionary at top; sandstone locally, fine-grained, lenticular, some marine megafossils; uranium deposits in upper part near Deweesville. Thickness 50 feet. Lies above Dilworth Sandstone Member and below Deweesville Sandstone Member (both of Whitsett). Age is Eocene.
Not separately mapped. [Present in McMullen, Atascosa, and Karnes Cos., southern TX.]
Source: Publication.
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 ([ ]).