The Laramie Formation is a geologic formation of the Late Cretaceous ( Maastrichtian ) age, named by Clarence King in 1876 for exposures in northeastern Colorado , in the United States . It was deposited on a coastal plain and in coastal swamps that flanked the Western Interior Seaway . It contains coal , clay and uranium deposits, as well as plant and animal fossils , including dinosaur remains. The formation contains some of the oldest records of Grass in western North America.
37-796: The Laramie Formation is exposed around the edges of the Denver Basin and ranges from 400–500 feet (120–150 m) on the western side of the basin, and 200–300 feet (60–90 m) thick on the eastern side. It rests conformably on the Fox Hills Sandstone and unconformably underlies the Arapahoe Conglomerate . The formation can be divided into an unnamed lower member containing bedded sandstone , clay and coal ; and an unnamed upper member composed predominately of 90 to 190 m of drab-colored mudstone , some sandstone, and thin coal beds. Nodular ironstone concretions occur in
74-525: A complex mortise and tenon –like joint connecting the dentary bones at the front of the jaw, teeth which are non- pedicellate and slightly tricuspid (bearing three cusps ), the frontal bones of the skull display raised polygonal sculpturing, and three anterior cervical components form an ' atlas – axis ' complex, similar to that of amniotes . The morphology of albanerpetontids suggests that they were sit-and-wait terrestrial predators and fed on invertebrates, similar to living plethodontids. The fact that
111-470: A four fingered forelimb (manus), ectochordal (spoon shaped with open centra) vertebrae with cylindrical centra, ribs that do not encircle the body, and a salamander-like quadrate – squamosal articulation, but are distinguished from the three living groups of lissamphibians by their possession of keratinized claw sheaths and their retention of skull bones lost in other lissamphibians, including epipterygoids , supraoccipitals and large palatines , as well as
148-587: Is currently very active, and the play is expanding into Perkins , Chase , and Dundy counties, Nebraska. Bituminous coal has been mined by underground methods in the Denver Basin, at Superior and Louisville, Colorado and other locations along the western edge of the basin. The coal comes from the Cretaceous Laramie Formation . Mining began in the late 1850s and stopped in 1979. Large lignite deposits are present in
185-492: Is estimated that about 130 million short tons of sub-bituminous coal were mined from the Laramie Formation between 1884 and 1979, mostly from seams in the lower part of the formation. Where the seams are relatively flat lying or gently dipping most of the mines were underground room and pillar operations, and where the seams are steeply inclined to vertical, stope mining was used. Relatively little surface mining
222-425: Is known from northern Spain, dating to around 2.2-2.6 million years ago. Albanerpetontids were long thought to be salamanders because of their small size and generalized body plans. However, these features are now thought to be ancestral for lissamphibians and not indicative of close relationships between the two groups. Albanerpetontids share with living lissamphibians an atlanto-occipital joint with two cotyles,
259-689: Is largely confined to Eurasia and North America , with remains also known from Morocco in North Africa. The first albanerpetontids are known from the western Palearctic (Europe and North Africa) in the Middle Jurassic ( Bathonian ~168–166 million years ago), with the oldest records of the group in North America and Asia dating to the Early Cretaceous . The last known remains of albanerpetontids in North America are from
296-473: Is supported by the internal vascularisation and lack of Sharpey's fibres in the frontal bones. Albanerpetontids are associated with both wet and dry environments, but it is unclear how tolerant they were of dry habitats, and they may have been confined to wet microhabitats in dry areas. Some authors have suggested that they were likely fossorial , using their heads to burrow, but this has been questioned by other authors. The distribution of albanerpetontids
333-752: The Fountain Formation , which is most prominently visible at Red Rocks and the Boulder Flatirons . The present basin was within the Cretaceous Interior Seaway , which deposited a thick Cretaceous section in the basin. Dinosaur fossils from the Maastrichtian have been unearthed in the Denver Basin. The basin was most likely further deepened in Paleogene time, between 66 and 45 million years ago, during
370-853: The Julesburg Basin , Denver-Julesburg Basin (after Julesburg, Colorado ), or the D-J Basin , is a geologic structural basin centered in eastern Colorado in the United States , but extending into southeast Wyoming , western Nebraska , and western Kansas . It underlies the Denver-Aurora Metropolitan Area on the eastern side of the Rocky Mountains . The basin consists of a large asymmetric syncline of Paleozoic , Mesozoic , and Cenozoic sedimentary rock layers, trending north to south along
407-586: The Laramide orogeny that created the modern Colorado Rockies. In particular, the uplifting of the Rockies in the Front Range caused the crust near Denver to buckle downward on the eastern side, deepening the basin. The basin later became filled with sediment eroded from the Rockies. The Front Range peaks rise approximately 22,000 ft (6600 m) from the floor of the basin under Denver. The deep part of
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#1732772493024444-710: The McKenzie Well , part of the Boulder oil field in Boulder County . The great majority of Denver Basin oil and gas fields produce from Cretaceous sandstones, although the Permian Lyons Sandstone is also a producer. Oil has also been produced from Permian sandstones and dolomites and Pennsylvanian limestones in the Nebraska part of the basin. The Wattenberg Gas Field , one of
481-549: The Morrison Formation beneath and to the west. Between Golden and Morrison, the Dakota hogback is called Dinosaur Ridge and is the site of a dinosaur trackway and dinosaur fossils exposed in the outcrop that are part of a Colorado State Natural Area and Geological Points of Interest. The Lyons and Lykins formations outcrop in a smaller hogback. Farther west, the Fountain Formation outcrops as flatirons and forms
518-642: The Niobrara Formation and Pierre Shale and made into cement at the Cemex plant near Lyons, Colorado . Sand and gravel for construction are a major mineral resource in the Denver Basin. The Lyons Formation provides flagstone from quarries in Boulder and Larimer counties, along the western edge of the basin. Small amounts of gold have been mined from sands and gravels in the Denver area since
555-585: The Paleocene Denver Formation in the central part of the basin, in a north-south belt east of Denver and Colorado Springs , in Adams , Arapahoe , Elbert , and El Paso counties. Some mining was done from about 1886 to 1940, but was reportedly minor. The Denver Basin aquifer system consists of a layered sequence of four aquifers in beds of permeable conglomerate, sandstone, and siltstone. Layers of relatively impermeable shale separate
592-840: The Paskapoo Formation in Canada, dating to the Paleocene . All other Cenozoic members of the family, belonging to the genus Albanerpeton , are known from Europe and Anatolia , from the Oligocene onwards (there is no fossil record of albanerpetontids during the Eocene ) until their final appearance in Northern Italy during the Early Pleistocene, around 2.13-2 million years ago. Another possible late record
629-813: The Pikes Peak Gold Rush of 1858. Some sand and gravel pits still recover gold in their washing operations. A small amount of uranium ore has been mined from the Dakota Sandstone at Morrison, Colorado , where the sandstone is impregnated with petroleum. Uranium is known to exist in roll-front type deposits in the Denver Basin, but the basin has never been a major source of uranium. 40°N 105°W / 40°N 105°W / 40; -105 ( Denver Basin ) Albanerpetontidae The Albanerpetontidae (also spelled Albanerpetidae and Albanerpetonidae ) are an extinct family of small amphibians , native to
666-416: The hyoid entoglossal process, which in life was embedded within the tongue. Analogous bones exists in chameleons and plethodontids, which allow rapid propulsion of the tongue. A hyoid entoglossal process is also known from Celtedens megacephalus , suggesting that the presence of a ballistic tongue is characteristic for the group. Distinguishing apomorphic traits characteristic of albanerpetontids include
703-531: The 9th largest source of natural gas in the United States. Biogenic natural gas is recovered from shallow gas fields (less than 3,000 feet) of the Niobrara Formation in Yuma , Phillips , and Washington counties of northeastern Colorado and Cheyenne and Sherman counties of northwestern Kansas . To date, 2,900 wells have produced 470 billion cubic feet (1.3 × 10 m ) of gas. Drilling
740-1641: The American Museum of Natural History. These specimens are very scrappy and the names no longer considered valid. Subsequent discoveries of dinosaurs occur through the formation, and include a nearly complete skull of Triceratops . Non-dinosaur vertebrates also occur (Carpenter 1979). More recent work in and around the Pawnee National Grasslands in Weld County has produced a diverse collection of 10 different fossil mammal species, including six multituberculates and four therians. List of Fossil Vertebrates (data from Carpenter 1979; Hutchinson and Holroyd 2003) Ischyriza cf. I. avonicola Sclerorhynchidae Lonchidion L. selachos Lonchidiidae Myledaphus M. bipartitus Rhinobatidae Squatirhina S. americana Ginglymostomatidae Amia Indeterminate Amiidae Atractosteus A. occidentalis Lepisosteidae Albanerpeton Indeterminate Albanerpetontidae Lisserpeton L. bairdi Scapherpetontidae Opisthotriton O. kayi Batrachosauroididae Scapherpeton S. tectum Scapherpetontidae Adocus Indeterminate Adocidae Basilemys cf. B. sinuosa Nanhsiungchelyidae Compsemys C. victa Pleurosternidae Helopanoplia cf. H. distincta Denver Basin The Denver Basin , variously referred to as
777-747: The American West (Carpenter and Young 2003). In 1873, Edward D. Cope accompanied Ferdinand V. Hayden , who was leader of the U.S. Geological and Geographical Survey of the Territories . The route of the expedition included eastern Colorado where Cope collected specimens in what is now the Laramie Formation along Bijou Creek on the east side of the Denver Basin (Cope, 1874). Cope named three species of dinosaurs without description: Cinodon arctatus (later changed to Cionodon arctatus ), Polyonax mortuarius and Agathaumas milo (later renamed Hadrosaurus occidentalis ). These specimens are currently in
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#1732772493024814-546: The Cretaceous of North America were assigned to the salamander genus Prosiren by Richard Estes in 1969, erecting the family Prosirenidae to accommodate the genus. Prosiren was originally described by Coleman J. Goin and Walter Auffenberg in 1958, based on vertebrae found in Cretaceous aged deposits in Texas. Albanerpeton , the type genus of the family was first named by Estes and Robert Hoffstetter in 1976 for
851-541: The Northern Hemisphere during the Mesozoic and Cenozoic . The only members of the order Allocaudata , they are thought to be allied with living amphibians belonging to Lissamphibia . Despite a superficially salamander-like bodyform, their anatomy is strongly divergent from modern amphibians in numerous aspects. The fossil record of albanerpetontids spans over 160 million years from the Middle Jurassic to
888-437: The absence of pedicellate teeth or a wide parasphenoid cultriform process. Albanerpetontids are now recognized as a distinct clade of lissamphibians separate from the three living orders of amphibians – Anura (frogs), Caudata (salamanders), and Gymnophiona (caecilians). Many studies show them as more closely related to frogs and salamanders than to caecilians, but bootstrap and Bayesian analyses show that this result
925-473: The aquifers and impede the vertical movement of ground water between the aquifers. The northern part of this aquifer system underlies the surficial aquifer of the South Platte River. Although the Denver Basin aquifer system and the surficial aquifer are hydraulically connected in part of this area, they primarily function as separate aquifer systems which serve as important sources of water supply in
962-574: The basin near Denver became filled with Paleogene sandstone and conglomerate , a layer now called the Denver Formation . In the regions to the north and south of Denver, however, stream erosion removed the Paleogene layers, revealing the underlying Cretaceous Pierre Shale . The basin itself forms a petroleum province. Oil and gas have been produced from the Denver Basin since the discovery in 1901 of oil in fractured Pierre Shale at
999-490: The beginning of the Pleistocene , about 2.13–2 million years ago. The earliest specimen of an albanerpetontid to be discovered was that of Celtedens megacephalus from the Early Cretaceous ( Albian ) Pietraroja Plattenkalk of Italy, described by Oronzio Gabriele Costa in 1864, and originally placed in the genus Triton, a junior synonym of the salamander genus Triturus . Jaw elements of albanerpetontids from
1036-529: The east side of the Front Range from the vicinity of Pueblo northward into Wyoming . The basin is deepest near Denver, where it reaches a depth of approximately 13,000 ft (3900 m) below the surface. The basin is strongly asymmetric: the Dakota Sandstone outcrops in a "hog-back" ridge near Morrison a few miles west of Denver, reaches its maximum depth beneath Denver, then ascends very gradually to its eastern outcrop in central Kansas . The Dakota hogback exposes Dakota Sandstone overlying and protecting
1073-638: The largest natural gas deposits in the United States , is a basin-centered gas field just north of the Denver metropolitan area. The field has produced more than 4.0 trillion cubic feet (TCF) of natural gas from the J Sandstone , Codell Sandstone , Niobrara Formation , and the Hygiene Sandstone , and Terry Sandstone members of the Pierre Shale , (all Cretaceous ). In 2007, the field made 11 million barrels of oil and 170 billion cubic feet (BCF) of gas from more than 14,000 wells, making it
1110-458: The mudstones that contain plant remains. Some of the material in the sandstones originated from silicic volcanoes far to the west. The coal and clay deposits of the Laramie Formation were once economically important. Clay mining began in the Golden, Colorado area in 1877 and continued until the mid-twentieth century. Most of the clay was used to make bricks and tiles for building construction. It
1147-882: The namesake of the Red Rocks Park and Amphitheatre . Here, against the eastern edge of the Rocky Mountain Front range, the Fountain Formation is in nonconformable contact with the Precambrian crystalline rock of the Idaho Springs Formation . The basin started forming as early as 300 million years ago, during the Colorado orogeny that created the Ancestral Rockies . Rocks formed during this time include
Laramie Formation - Misplaced Pages Continue
1184-497: The region. Denver and its suburbs such as the communities in Douglas County draw ground water from the aquifers in the Denver Basin. There is recharge of about 40,000 acre-feet per year from the broken land to the west of the basin and withdrawals of about 10 times as much. Ground water levels have dropped in the aquifers especially near population centers which draw on the aquifers for water. Raw materials are mined from
1221-469: The skull of the juvenile paratype of Yaksha was around 1/4 of the size of the adult suggests that albanerpetontids grew by direct development and did not have a metamorphic larval stage. It has been suggested that albanerpetontids absorbed oxygen entirely through the skin via cutaneous respiration and lacked lungs like plethodontid salamanders, due to the length of the hyoid entoglossal process, which may have made normal breathing difficult. This proposal
1258-497: The species of A. inexpectatum described from a large number of jaws and frontal bones from a Miocene aged fissure fill deposit near Saint-Alban-de-Roche in France, and was initially classified as a salamander, and placed in the family Prosirenidae alongside Prosiren due to the morphological similarity with the jaw fragments attributed to Prosiren by Estes (1969). Richard Fox and Bruce Naylor in 1982 realised that Albanerpeton
1295-540: Was done. The Laramie Formation also hosts uranium deposits. The Leyden Coal Mine produced uranium for a few years as a byproduct of the coal mining. Uranium deposits also occur in sandstones of the Laramie Formation in Weld County, Colorado , and near the town of Grover, Colorado . (See Uranium mining in Colorado ) Fossil vertebrates from the Laramie Formation were among the first dinosaurs to be discovered in
1332-418: Was embedded with bony, fish-like scales. The forelimbs only had four digits , while retaining five digits on the hindlimbs. The morphology of the complete three-dimensionally preserved skull of Yaksha peretti suggests that albanerpetontids had ballistic tongues akin to those of chameleons and plethodontid salamanders, as evidenced by the presence of an elongated rod shaped bone in the jaw cavity, dubbed
1369-511: Was not a salamander, noting that the holotype vertebra of Prosiren was different to those of albanerpetontids, concluding that Albanerpeton was "well isolated from salamanders" and that it "seems no nearer phyletically to any other known amphibians, from Devonian to Recent" erecting the family Albanerpetontidae and the order Allocaudata to accommodate it. Albanerpetontids were small (several cm to several tens of centimetres in length) and superficially lizard-like. The skin of albanerpetontids
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