The Red Beds of Texas and Oklahoma are a group of

Early Permian 01 or '01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * 01'' (Richard Müller album), 2001 * ''01'' (Son of Dave album), 2000 * ''01'' (Urban Zakapa album), 2011 * ''O1'' (Hiroyuki Sawan ...

-age geologic strata in the southwestern United States cropping out in north-central

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

and south-central

Oklahoma Oklahoma (; Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a state in the South Central region of the United States, bordered by Texas on the south and west, Kansas on the north, Missouri on the northeast, Arkansas on the east, New ...

. They comprise several stratigraphic

groups A group is a number of persons or things that are located, gathered, or classed together. Groups of people * Cultural group, a group whose members share the same cultural identity * Ethnic group, a group whose members share the same ethnic ide ...

including the

Clear Fork Group The Clear Fork Group is a geologic group in the Texas Red Beds. It preserves fossils dating back to the Permian period. See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas Paleontology in Texas refers to pa ...

, the

Wichita Group The Wichita Group is a geologic group in the Texas Red Beds. It preserves fossils dating back to the Permian period. See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas Paleontology in Texas refers to paleont ...

, and the

Pease River Group The Pease River Group is a geologic group in Texas Red Beds. It preserves fossils dating back to the Permian period. See also * List of fossiliferous stratigraphic units in Texas * Paleontology in Texas Paleontology in Texas refers to paleont ...

.Nelson, John W., Robert W. Hook, and Dan S. Chaney (2013)
Lithostratigraphy of the Lower Permian (Leonardian) Clear Fork Formation of North-Central Texas
from The Carboniferous-Permian Transition: Bulletin 60, ed. Spencer G. Lucas et al. New Mexico Museum of Natural History and Science, pg. 286-311. Retrieved December 28, 2017. The Red Beds were first explored by American paleontologist

Edward Drinker Cope Edward Drinker Cope (July 28, 1840 – April 12, 1897) was an American zoologist, paleontologist, comparative anatomist, herpetologist, and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interes ...

starting in 1877.Cope, E.D. (1878)
Descriptions of Batrachia and Reptilia from the Permian Formation of Texas.
Proceedings of the American Philosophical Society, vol. 17, no. 101, pg. 505-30. Retrieved December 28, 2017. Fossil remains of many Permian

tetrapods Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids (reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct therapsi ...

(four-limbed vertebrates) have been found in the Red Beds, including those of ''

Dimetrodon ''Dimetrodon'' ( or ,) meaning "two measures of teeth,” is an extinct genus of non-mammalian synapsid that lived during the Cisuralian (Early Permian), around 295–272 million years ago (Mya). It is a member of the family Sphenacodont ...

'', ''

Edaphosaurus ''Edaphosaurus'' (, meaning "pavement lizard" for dense clusters of teeth) is a genus of extinct edaphosaurid synapsids that lived in what is now North America and Europe around 303.4 to 272.5 million years ago, during the Late Carboniferous to ...

'', '' Seymouria'', ''

Platyhystrix ''Platyhystrix'' (from el, πλατύς , 'flat' and el, ῠ̔́στρῐξ , 'porcupine') was a temnospondyl amphibian with a distinctive sail along its back, similar to the unrelated synapsids, ''Dimetrodon'' and '' Edaphosaurus''. It lived d ...

'', and ''

Eryops ''Eryops'' (; from Greek , , 'drawn-out' + , , 'face', because most of its skull was in front of its eyes) is a genus of extinct, amphibious temnospondyls. It contains the single species , the fossils of which are found mainly in early Permian (a ...

''. A recurring feature in many of these animals is the sail structure on their backs. EdaphosaurusDB

Location

Deposits dating from the

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleo ...

are present contiguously stretching from central Texas all the way into southern

Nebraska Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the sout ...

.King, Philip B., and Helen M. Beikman (1976)
The Paleozoic and Mesozoic Rocks; A Discussion to Accompany the Geologic Map of the United States.
United States Geological Survey, Professional Paper 903, pg. 29-32. Retrieved December 29, 2017. In Nebraska and

Kansas Kansas () is a U.S. state, state in the Midwestern United States, Midwestern United States. Its Capital city, capital is Topeka, Kansas, Topeka, and its largest city is Wichita, Kansas, Wichita. Kansas is a landlocked state bordered by Nebras ...

, deposits of light-colored limestone are frequent, while red-colored rocks are rare. In Oklahoma, the light-colored

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms w ...

transitions gradually into red-colored

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicat ...

and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

until the limestone is virtually nonexistent in north-central

.Case, E.C. (1915)
Chapter 1: Description of the Southern Portion of the Plains Province
in The Permo-Carboniferous Red Beds of North America and Their Vertebrate Fauna. Carnegie Institute of Washington, pg. 5-61. Retrieved December 29, 2017. The portion of the red beds with abundant fossil deposits is in Texas between the Red River and the Salt Fork Brazos River.Benton, Michael (2001)
Chapter Three: Four Feet on the Ground
from The Book Of Life: An Illustrated History of the Evolution of Life on Earth, ed. Stephen Jay Gould. W.W. Norton: pg. 93-5. Retrieved December 28, 2017. The area includes the city of

Wichita Falls Wichita Falls ( ) is a city in and the seat of government of Wichita County, Texas, United States. It is the principal city of the Wichita Falls Metropolitan Statistical Area, which encompasses all of Archer, Clay, and Wichita counties. According ...

, and rural communities such as

Seymour Seymour may refer to: Places Australia * Seymour, Victoria, a township * Electoral district of Seymour, a former electoral district in Victoria * Rural City of Seymour, a former local government area in Victoria * Seymour, Tasmania, a localit ...

and Archer City.Barnes, V.E., et al. (1987)
Geologic atlas of Texas, Wichita Falls-Lawton sheet.
University of Texas at Austin Bureau of Economic Geology. Retrieved December 28, 2017.

Properties

The Texas and Oklahoma red beds are

sedimentary rock Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles ...

s, mostly consisting of sandstone and red

mudstone Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from '' shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.' ...

.Sander, P. Martin (1989)
Early Permian depositional environments and pond bonebeds in central Archer County, Texas.
Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 69, pg. 1-21. Retrieved December 28, 2017. The red color of the rocks is due to the presence of

ferric oxide Iron(III) oxide or ferric oxide is the inorganic compound with the formula Fe2O3. It is one of the three main oxides of iron, the other two being iron(II) oxide (FeO), which is rare; and iron(II,III) oxide (Fe3O4), which also occurs naturall ...

.Van Houten, Franklin (1973)
Origin of Red Beds: A review - 1961-1972.
Annual Review of Earth and Planetary Sciences, Vol. 1, pg. 39-61. Retrieved December 28, 2017. The rocks were deposited during the early Permian in a warm, moist climate,Baker, Charles Laurence (1916)
Origin of Texas Red Beds.
Bulletin of the

University of Texas The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...

, No. 26. Retrieved December 28, 2017. with seasonal periods of dry conditions.Chaney, D.S., and W.A. DiMichele (2007).
Paleobotany of the classic redbeds of north central Texas.
Proceedings of the XVth International Congress on Carboniferous and Permian Stratigraphy, pg. 357-66. The Netherlands: Utrecht. Retrieved December 29, 2017.

Stratigraphy

The Texas and Oklahoma red beds can be split into three primary

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostra ...

groups: the

, the

, and the

. The Wichita Group is the oldest of the three groups, having been deposited in the Sakmarian age.Johnson, Garyd (2013)
Xenacanth Sharks and other Vertebrates from the Geraldine Bonebed, Lower Permian of Texas
from The Carboniferous-Permian Transition: Bulletin 60, ed. Spencer G. Lucas et al. New Mexico Museum of Natural History and Science, pg. 161-7. Retrieved December 28, 2017. The Wichita Group contains some of the richest fossil deposits in the red beds, including the Geraldine Bonebed in Archer County. The Pease River Group is the most recent deposition, occurring during the

Guadalupian The Guadalupian is the second and middle series/ epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 � ...

epoch. The Clear Fork Group is in between the other two, being deposited during the Kungurian age. The stratigraphic groups are layered such that the Pease River Group overlies the Clear Fork Group, which overlies the Wichita group.

Fossil record

In 1877, Edward Drinker Cope was the first

paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

to study the red beds in search of

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s. Cope employed collectors to aid him in his search for bones, including Swiss botanist

Jacob Boll Jacob Boll (28 May 1828 – 29 September 1880) was a Swiss naturalist and entomologist especially noted for his exploration of the Texas Red Beds. Boll was born 1828 in Würenlos, Switzerland, and educated as a pharmacist in Switzerland and Ger ...

. After Boll's death in 1880 while collecting, Cope employed a preacher named W.F. Cummins to continue the search. After Cope, paleontologists such as Ermine Cowles CaseCase, E.C. (1914)
The Red Beds between Wichita Falls, Texas, and Las Vegas, New Mexico, in Relation to their Vertebrate Fauna.
The Journal of Geology, vol. 22, no. 3, pg. 243-59. Retrieved December 28, 2017. and

Alfred Romer Alfred Sherwood Romer (December 28, 1894 – November 5, 1973) was an American paleontologist and biologist and a specialist in vertebrate evolution. Biography Alfred Romer was born in White Plains, New York, the son of Harry Houston Romer an ...

Romer, Alfred, and Llewellyn Price (1940)
Review of the Pelycosauria.
Geological Society of America, Vol. 28, Special Paper. Retrieved December 28, 2017. found rich deposits of Permian-era

tetrapod Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids ( pelycosaurs, extinct t ...

Geraldine Bonebed

The most prolific fossil site in the red beds is the Geraldine Bonebed within the Wichita Group. During the Permian, the bonebed was the site of a freshwater pond, which after a catastrophic event, became the burial site for a variety of terrestrial and marine animals.Sander, P. Martin (1987)
Taphonomy of the Lower Permian Geraldine Bonebed in Archer County, Texas.
Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 61, pg. 221-36. Retrieved December 28, 2017. As a result, the bonebed contains a cross-section of life during the early Permian. Plant remains found in the bonebed include ''

Calamites ''Calamites'' is a genus of extinct arborescent (tree-like) horsetails to which the modern horsetails (genus '' Equisetum'') are closely related. Unlike their herbaceous modern cousins, these plants were medium-sized trees, growing to heights o ...

'',

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

s, and

conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All ext ...

. Marine life present in the bonebed include ''

Xenacanthus ''Xenacanthus'' (from Ancient Greek ξένος, xénos, 'foreign, alien' + ἄκανθος, akanthos, 'spine') is a genus of prehistoric sharks. The first species of the genus lived in the later Devonian period, and they survived until the end o ...

'',

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

s, and

lungfish Lungfish are freshwater vertebrates belonging to the order Dipnoi. Lungfish are best known for retaining ancestral characteristics within the Osteichthyes, including the ability to breathe air, and ancestral structures within Sarcopterygii, i ...

. The Geraldine Bonebed is most famous as a prolific source of temnospondyls,

synapsids Synapsids + (, 'arch') > () "having a fused arch"; synonymous with ''theropsids'' (Greek, "beast-face") are one of the two major groups of animals that evolved from basal amniotes, the other being the sauropsids, the group that includes rept ...

, basal

reptiliomorphs Reptiliomorpha (meaning reptile-shaped; in PhyloCode known as ''Pan-Amniota'') is a clade containing the amniotes and those tetrapods that share a more recent common ancestor with amniotes than with living amphibians (lissamphibians). It was def ...

and

reptiles Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates ( lizards and snakes) and rhynchoceph ...

, including partial and complete skeletons of '' Archeria'', ''

'', ''

'', '' Bolosaurus'', '' Trimerorhachis'', ''

Zatrachys ''Zatrachys'' is an extinct genus of large and flat-headed zatracheidid temnospondyl from the early Permian of North America. History of study ''Zatrachys'' was named by American paleontologist Edward Drinker Cope in 1878 for the type speci ...

'', and '' Ophiacodon''.

Clear Fork deposits

The Clear Fork Group also contains multiple fossil sites. Like the Geraldine Bonebed and other Wichita Group sites, the Clear Fork Group is most famous for its early Permian amphibian deposits, especially '' Seymouria baylorensis''. The species and genus were first discovered in 1904 by German paleontologist Ferdinand Broili.Williston, S.W. (1911)
Restoration of ''Seymouria baylorensis'' Broili, an American Cotylosaur.
The Journal of Geology, vol. 19, no. 3, pg. 232–7. Retrieved December 29, 2017. ''Seymouria baylorensis'' is named for the location of its discovery in

Baylor County Baylor County is a county located in the U.S. state of Texas. As of the 2020 census, its population was 3,465. Its county seat is Seymour. History In 1858, the Texas Legislature established Baylor County, naming it for Henry Weidner Baylor ...

near the city of

. As one of the few ''Seymouria'' bone sites in the world, paleontologists have studied the Clear Fork deposit for evidence of ''Seymouria'' as a

transitional fossil A transitional fossil is any fossilized remains of a life form that exhibits traits common to both an ancestral group and its derived descendant group. This is especially important where the descendant group is sharply differentiated by gross a ...

between aquatic and terrestrial animals, as well as ''Seymourias close relationship to

amniote Amniotes are a clade of tetrapod vertebrates that comprises sauropsids (including all reptiles and birds, and extinct parareptiles and non-avian dinosaurs) and synapsids (including pelycosaurs and therapsids such as mammals). They are dis ...

s.Laurin, Michel (1996)
A redescription of the cranial anatomy of ''Seymouria baylorensis'', the best known seymouriamorph.
PaleoBios, Vol. 17, no. 1, pg. 1-16. Retrieved December 29, 2017.Carrol, Robert L., and Robert B. Holmes (2008)
Evolution of the Appendicular Skeleton of Amphibians
from Fins into Limbs: Evolution, Development, and Transformation, ed. Brian K. Hall. University of Chicago Press, pg. 206-9. The Clear Fork Group also contains deposits of plant species throughout its different sections. The increasing prevalence of seed plants with pockets of water-based plants can be used to infer a wet, but drying climate.

References

{{reflist Geology of Texas Geology of Oklahoma Permian paleontological sites