In geology, Neocomian was a name given to the lowest stage of the Cretaceous system. It is generally considered to encompass the interval now covered by the Berriasian, Valanginian and Hauterivian, from approximately 145 to 130 Ma. It was introduced by Jules Thurmann in 1835 on account of the development of these rocks at Neuchâtel (Neocomum), Switzerland. It has been employed in more than one sense. In the type area the rocks have been divided into two sub-stages, a lower, Valanginian and an upper, Hauterivian ; there is also another local sub-stage, the infra-Valanginian or Berriasian. These three sub-stages constitute the Neocomian in its restricted sense. Adolf von Koenen and other German geologists extend the use of the term to include the whole of the Lower Cretaceous up to the top of the Gault or Albian. Eugène Renevier divided the Lower Cretaceous into the Neocomian division, embracing the three sub-stages mentioned above, and an Urgonian division, including the Barremian, Rhodanian and Aptian sub-stages. Sir A. Geikie regards Neocomian as synonymous with Lower Cretaceous, and he, like Renevier, closes this portion of the system at the top of the Lower Greensand (Aptian). Other British geologists restrict the Neocomian to the marine beds of Speeton and Tealby, and their estuarine equivalents, the Weald Clay and Hastings Sands (Wealden). Much confusion would be avoided by dropping the term Neocomian entirely and employing instead, for the type area, the sub-divisions given above. This becomes the more obvious when it is pointed out that the Berriasian type is limited to Dauphine; the Valanginian has not a much wider range; and the Hauterivian does not extend north of the Paris basin.
The Cedar Mountain Formation is the name given to a distinctive sedimentary geologic formation in eastern Utah, spanning most of the early and mid-Cretaceous. The formation was named for Cedar Mountain in northern Emery County, Utah, where William Lee Stokes first studied the exposures in 1944.
The Cloverly Formation is a geological formation of Early and Late Cretaceous age that is present in parts of Montana, Wyoming, Colorado and Utah in the western United States. It was named for a post office on the eastern side of the Bighorn Basin in Wyoming by N.H. Darton in 1904. The sedimentary rocks of formation were deposited in floodplain environments and contain vertebrate fossils, including a diverse assemblage of dinosaur remains. In 1973, the Cloverly Formation Site was designated as a National Natural Landmark by the National Park Service.
The Cryptobranchoidea are a suborder of salamanders found in Asia, European Russia, and the United States. They are known as primitive salamanders, in contrast to Salamandroidea, the advanced salamanders. It has two living subdivisions, Cryptobranchidae, which includes Asian giant salamanders and hellbenders, and Hynobiidae, commonly known as Asian salamanders.
Sinemys is an extinct genus of turtle from the Late Jurassic to Early Cretaceous of China and Japan. Three species have been named: S. lens, the type species, from the Kimmeridgian-Tithonian of Shandong; S. gamera, from the Valanginian-Albian of Nei Mongol; and S. wuerhoensis, from the Aptian-Albian of Xinjiang. The species S. gamera is noted for the presence of a pair of elongate spines projecting outwards and backwards from seventh costal of the carapace. These may have served a hydrodynamic function.
The Magallanes Basin or Austral Basin is a major sedimentary basin in southern Patagonia. The basin covers a surface of about 170,000 to 200,000 square kilometres and has a NNW-SSE oriented shape. The basin is bounded to the west by the Andes mountains and is separated from the Malvinas Basin to the east by the Río Chico-Dungeness High. The basin evolved from being an extensional back-arc basin in the Mesozoic to being a compressional foreland basin in the Cenozoic. Rocks within the basin are Jurassic in age and include the Cerro Toro Formation. Three ages of the SALMA classification are defined in the basin; the Early Miocene Santacrucian from the Santa Cruz Formation and Friasian from the Río Frías Formation and the Pleistocene Ensenadan from the La Ensenada Formation.
The Meng-Yin or Mengyin Formation is a geological formation in Shandong, China, whose strata date back to the Berriasian and Valanginian stages of the Early Cretaceous.
The Luohandong Formation is an Early Cretaceous geologic formation of the Ordos Basin in Inner Mongolia, China. The formation was initially dated to the earliest Cretaceous; Valanginian to Barremian, but later dating established an Aptian to Albian age. Dinosaur remains are among the fossils that have been recovered from the formation. Pterosaur fossils have also been recovered from the formation.
Mesoraphidiidae is an extinct family of snakeflies in the suborder Raphidiomorpha. The family lived from the Late Jurassic through the Late Cretaceous and is known from twenty-five genera. Mesoraphidiids have been found as both compression fossils and as inclusions in amber. The family was first proposed in 1925 by the Russian paleoentomologist Andrey Vasilyevich Martynov based on Upper Jurassic fossils recovered in Kazakhstan. The family was expanded in 2002 by the synonymizing of several other proposed snakefly families. The family was divided into three subfamilies and one tribe in a 2011 paper, further clarifying the relationships of the included genera.
Lytoceratinae is a subfamily of ammonoid cephalopods that make up part of the family Lytoceratidae.
The Ilek Formation is a Lower Cretaceous geologic formation in Western Siberia. Many different fossils have been recovered from the formation. It overlies the Late Jurassic Tyazhin Formation and underlies the Albian Kiya Formation.
Macrobaenidae is an extinct family of turtles, known from the Early Cretaceous to Paleogene of Laurasia. Their relationships to other turtles and whether they form a monophlyletic group are controversial. They are typically interpreted as stem or crown group cryptodires, but some more recent analyses have found them to lie outside crown group Testudines. Macrobaenids can be distinguished from other testudinatans by the presence of a carotid fenestra, cruciform plastron with strap-like epiplastra, and a lack of extragulars.
The Helochelydridae are an extinct family of stem-turtles known from fossils found in North America and Europe spanning the Early to Late Cretaceous.
Xinjiangchelyidae is an extinct family of turtles known from the Lower Jurassic to the Middle Cretaceous of Asia and western Europe. They have generally been interpreted as either being basal cryptodires or placed outside of crown Testudines.
Timeline showing the development of the extinct reptilian order Pterosauria from its appearance in the late Triassic period to its demise at the end of the Cretaceous, together with an alphabetical listing of pterosaur species and their geological ages.
Leyvachelys is an extinct genus of turtles in the family Sandownidae from the Early Cretaceous of the present-day Altiplano Cundiboyacense, Eastern Ranges, Colombian Andes. The genus is known only from its type species, Leyvachelys cipadi, described in 2015 by Colombian paleontologist Edwin Cadena. Fossils of Leyvachelys have been found in the fossiliferous Paja Formation, close to Villa de Leyva, Boyacá, after which the genus is named. The holotype specimen is the oldest and most complete sandownid turtle found to date.
Helochelydra is an extinct genus of extinct stem turtle known from the Early Cretaceous (Barremian) of the Isle of Wight, southern England.
The Bulldog Shale is a formation of Early Cretaceous age that forms part of the Marree Subgroup of the Rolling Downs Group, located in the Eromanga Basin of South Australia, Queensland and New South Wales.
Mesoblattinidae is an extinct family of cockroaches known from the Mesozoic. It was formerly considered a wastebasket taxon for Mesozoic cockroaches, but the family has subsequently been better defined, with many taxa transferred to Caloblattinidae. It is considered to have close affinities with Blattidae and Ectobiidae, as well as possibly Blaberidae. The family first appeared by the Early Jurassic. They are considered to represent amongst the oldest groups of modern cockroaches, and like them are thought to have laid oothecae.
Dortokidae is an extinct family of freshwater pan-pleurodiran turtles, known from the Cretaceous and Paleocene of Europe. Only four species have been named, but indeterminate fossils show that they were abundant across western and eastern-central Europe during the Cretaceous. The family is only known from postcranial remains.
