- Usage in publication:
-
- McGraw limestone
- Modifications:
-
- Named
- Dominant lithology:
-
- Limestone
- AAPG geologic province:
-
- Appalachian basin
Summary:
Named the McGraw limestone for McGraw Gap, Alleghany Co., VA. Consists of well-bedded heavy-ledged brittle, rather pure calcitite. Generally occurs as 6 in. to 1 ft. ledges and irregularly laminated and having thin calcarenite lenses. Thickness is 9 feet at type section and reaches 40 feet with thinning occurring to southeast. Unit overlies the McGlone limestone with a sharp contact and unconformably underlies the Nealmont limestone. The McGraw is of Middle Ordovician age.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- McGraw
- Modifications:
-
- Revised
- AAPG geologic province:
-
- Appalachian basin
Summary:
The McGraw limestone is not used in western VA and rocks previously assigned to this interval are included in the McGlone limestone. The upper 12 feet of the McGlone is a fine-grained, gray limestone with yellow-brown argillaceous partings.
Source: GNU records (USGS DDS-6; Reston GNULEX).
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 ([ ]).