The Britton Formation is a geologic
formation deposited during the Middle
Cenomanian
The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...
to the Early
Turonian ages of the Late
Cretaceous in modern-day
East Texas.
It forms the lower half of the
Eagle Ford Group in the northern portion of
East Texas. The formation was named by W. L. Moreman in 1932 for outcrops on Mountain Creek near the small town of Britton, south of
Dallas.
In the
Dallas area it has been subdivided into the Six Flags Limestone, Turner Park Member, and Camp Wisdom Member.
[Reaser, D. F. (2002) Geology of the Dallas-Ft. Worth Metroplex and local geologic/meteorologic hazards: Upper Saddle River, New Jersey, Pearson Custom Publishing, 193 p.] The Six Flags Limestone is a 3 ft (1 m) thick
fossiliferous
calcarenite made up of pieces (prisms) of ''
Inoceramus'' clams. The Turner Park and Camp Wisdom Members were subdivided based on the numerous
volcanic ash beds (bentonites) found in the Turner Park, and the common occurrence of
concretions in the Camp Wisdom. They are approximately 120 ft (37 m) (Turner Park) and 250 ft (76 m) (Camp Wisdom) thick in the
Dallas area.
Thin
sandstones known as the Templeton Member are found in
Grayson County, north of
Dallas, that are age equivalent to the lower part of the Turner Park Member. The Templeton Member was originally described as a part of the
Woodbine, but it was recently placed in the Britton Formation of the
Eagle Ford Group based on its age as derived by
ammonite
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...
s.
Plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared ...
remains are among the
vertebrate fossils that have been recovered from its strata.
[Timothy S. Myers (2015) First North American occurrence of the toothed pteranodontoid pterosaur ''Cimoliopterus''. Journal of Vertebrate of Paleontology (advance online publication) DOI:10.1080/02724634.2015.1014904 http://www.tandfonline.com/doi/full/10.1080/02724634.2015.1014904]
Paleofauna
Vertebrate fossils found in the Britton Formation include
plesiosaur
The Plesiosauria (; Greek: πλησίος, ''plesios'', meaning "near to" and ''sauros'', meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia.
Plesiosaurs first appeared ...
s and
shark teeth.
s found in the Britton Formation include
crustaceans,
ammonite
Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttlefish) ...
s, ''
Inoceramus'',
foraminifera, and
ostracods.
[Stenzel, H. B. (1952) Decapod crustaceans from the Woodbine Formation of Texas: USGS Professional Paper 242, p. 212-217.]
References
See also
{{Portal, Earth sciences, Paleontology, , }
*
Plesiosaur stratigraphic distribution
Cretaceous geology of Texas