Word Formation

This article is about the geological formation. For the linguistics term, see Word formation.

Word Formation
Stratigraphic range: Roadian-Wordian ~272–265.1  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Fossil from the Word Formation
Type	Formation
Sub-units	Appel Ranch, China Tank & Willis Ranch members
Overlies	Road Canyon Formation
Lithology
Primary	Limestone
Location
Coordinates	30°24′N103°12′W / 30.4°N 103.2°W / 30.4; -103.2
Approximate paleocoordinates	1°36′N33°00′W / 1.6°N 33.0°W / 1.6; -33.0
Region	Texas
Country	United States
Extent	Glass Mountains
Type section
Named for	Old Word Ranch
Word Formation (the United States) Show map of the United States Word Formation (Texas) Show map of Texas

The Word Formation is a geologic formation in Texas. ^[1] It preserves fossils dating back to the Permian period. It is probably named for the Old Word Ranch in the Glass Mountains of Brewster County. ^[2]

Defining formation

The Wordian age of the Permian Period is named for the Word Formation. ^[3]

Subdivisions

The formation is subdivided into three members, from young to old:

• Appel Ranch - Wordian ^[4]
• China Tank - Roadian ^[5]
• Willis Ranch - Roadian ^[6]

Fossil content

The limestone formation contains marine gastropods, brachiopods and ammonites. ^[1]

Vertebrate paleofauna

• Helicoprion davisii

See also

• List of fossiliferous stratigraphic units in Texas
• Paleontology in Texas

References

1. Word Formation at Fossilworks.org
2. Word Formation by USGS, retrieved 5 January 2017
3. Old Word Ranch, Glass Mountains at Fossilworks.org
4. Appel Ranch member at Fossilworks.org
5. China Tank member at Fossilworks.org
6. Willis Ranch member at Fossilworks.org

Further reading

• M. Kelly and R. Zangerl. 1976. Helicoprion (Edestidae) in the Permian of West Texas. Journal of Paleontology 50(5):992-994
• G. A. Cooper and R. E. Grant. 1972. Permian brachiopods of west Texas, I. Smithsonian Contributions to Paleobiology 14:1-231
• R. L. Batten. 1958. Permian Gastropoda of the southwestern United States. 2. Pleurotomariacea: Portlockiellidae, Phymatopleuridae, and Eotomariidae. Bulletin of the American Museum of Natural History 114(2):153-246
• E. L. Yochelson. 1956. Permian Gastropoda of the southwestern United States. 1. Euomphalacea, Trochonematacea, Pesudophoracea, Anomphalacea, Craspedostomatacea, and Platyceratacea. Bulletin of the American Museum of Natural History 110(3):173-276
• A. K. Miller and W. M. Furnish. 1940. Permian ammonoids of the Guadalupe Mountain region and adjacent area. Geological Society of America Special Paper 26:1-242
• F. B. Plummer and G. Scott. 1937. Upper Paleozoic ammonites in Texas. The University of Texas Bulletin 3701:1-516
• R. E. King. 1931. The Geology of the Glass Mountains, Texas, Part II, Faunal summary and correlation of the Permian formations with description of Brachiopoda. The University of Texas Bulletin 3042:1-245
• G. H. Girty. 1909. The Guadalupian fauna. United States Geological Survey Professional Paper 58:1-651