The Morrison Formation is a geological formation laid down in the Upper Jurassic. It is a distinctive sequence of sedimentary rock in the western United States, and is named after Morrison, Colorado. It has been the most fertile source of dinosaur fossils in North America.
It is composed of mudstone, sandstone, siltstone and limestone. Its colour is light grey, greenish gray, or red. Most of the fossils occur in the green siltstone beds and lower sandstones, relics of the rivers and floodplains of the Jurassic period.
The formation is in Wyoming and Colorado, with outcrops in Montana, North Dakota, South Dakota, Nebraska, Kansas, the panhandles of Oklahoma and Texas, New Mexico, Arizona, Utah, and Idaho. Equivalent rocks under different names are found in Canada. It covers an area of 1.5 million square km (600,000 square miles), although only a tiny fraction is exposed and accessible to geologists and paleontologists. Over 75% is still buried under the prairie to the east and much of the rest was destroyed by erosion as the Rocky Mountains rose to the west.
The first fossils were discovered by Arthur Lakes in 1877. That same year, it became the center of the Bone Wars, a fossil-collecting rivalry between early paleontologists Othniel Charles Marsh and Edward Drinker Cope.
In Colorado, New Mexico, and Utah, the Morrison Formation was a major source of uranium ore.
According to radiometric dating, the Morrison Formation dates from 156.3 ± 2 million years old at its base, to 146.8 ± 1 million years old at the top, which places it in the later Jurassic. This is similar in age to the Solnhofen Limestone Formation in Germany and the Tendaguru Formation in Tanzania. Throughout the western USA, it lays over the Middle Jurassic Summerville, Sundance, Bell Ranch, Wanakah, and Stump Formations.
At the time, the supercontinent of Laurasia had recently split into the continents of North America and Eurasia, although they were still connected by land bridges. North America moved north and was passing through the subtropical regions.
The area was low-lying, and sediments were laid down in rivers, lakes, shallow water of various kinds. The details varied from time to time.
The Morrison Basin, which stretched from New Mexico in the south to Alberta and Saskatchewan in the north, was formed when the early pre-Rocky Mountains started pushing up to the west. Streams and rivers in the east-facing drainage basin swept sediment down from the heights. The sediment was dropped in swampy lowlands, lakes, river channels and floodplains. In the course of time, this became the Morrison Formation.
In the north, the Sundance Sea, an extension of the Arctic Ocean, stretched through Canada down to the United States. Coal is found in the Morrison Formation of Montana, which means that the northern part of the formation, along the shores of the sea, was wet and swampy, with much vegetation. Aeolian, or wind-deposited sandstones are found in the southwestern part, which indicates it was much more arid — a desert, with sand dunes.
Dinosaur National Monument is a National Monument on the southeast flank of the Uinta Mountains on the border between Colorado and Utah at the confluence of the Green and Yampa Rivers. The "Dinosaur Quarry" is in Utah just to the north of the town of Jensen, Utah. This park has fossils of dinosaurs including "Allosaurus", "Abydosaurus" (a nearly complete skull, lower jaws and first four neck vertebrae of the specimen DINO 16488 was found here) and various long-neck, long-tail sauropods.
The dinosaur fossil beds (bone beds) were discovered in 1909 by Earl Douglass, a paleontologist working and collecting for the Carnegie Museum. He and his crews excavated thousands of fossils and shipped them back to the museum in Pittsburgh, Pennsylvania for study and display. President Woodrow Wilson proclaimed the dinosaur beds as Dinosaur National Monument in 1915. The monument boundaries were expanded in 1938 from the original tract surrounding the dinosaur quarry in Utah, to its present extent of over 200,000 acres (800 km²) in Utah and Colorado, including the spectacular river canyons of the Green and Yampa.
The roster of dinosaurs from the Morrison is impressive. Among the theropods, "Allosaurus", "Saurophaganax", "Torvosaurus", "Ceratosaurus", "Coelurus", "Ornitholestes", "Tanycolagreus", "Stokesosaurus", and "Marshosaurus" are found in the Morrison. An abundance of sauropods has been found there, including "Apatosaurus", "Diplodocus", "Barosaurus", "Brachiosaurus", "Camarasaurus", and "Amphicoelias", which is possibly the largest known dinosaur ever to exist. Two genera of stegosaurs, "Stegosaurus" and "Hesperosaurus", have been found there. Finally, ornithopods found in the Morrison include "Dryosaurus", "Camptosaurus", "Drinker", "Othnielia", and "Othnielosaurus".
Ichinobe-no Oshiwa
No firm dates can be assigned to the lives or reigns of this period, but the reign of Emperor Ankō is considered to have lasted from 456 to 479; and Oshiwa died during Ankō's reign.
According to the "Nihonshoki", Oshiwa was killed in a hunting accident by Emperor Yūryaku. His sons were adopted as heirs by Emperor Seinei. They are known as Prince Woke (or Kenzō"-tennō") and as Prince Oke (or Ninken"-tennō").
Dinosaur Ridge
Dinosaur Ridge is part of the Morrison Formation, just west of Denver.
The Dinosaur Ridge area is one of the world's most famous dinosaur fossil localities. In 1877, some of the best-known dinosaurs were found here, including "Apatosaurus", "Diplodocus", "Stegosaurus", and "Allosaurus".
In 1973, the area was recognized for its uniqueness as well as its historical and scientific significance when it was designated the Morrison Fossil Area National Natural Landmark by the National Park Service. In 1989, the Friends of Dinosaur Ridge formed to address increasing concerns regarding the preservation of the site and to offer educational programs on the area's resources.
The rocks on the west side of Dinosaur Ridge are part of the widespread Morrison Formation of Jurassic age. It is in these rocks, where Arthur Lakes discovered the dinosaur bones in 1877. Fifteen quarries were opened along the Dakota hogback in the Morrison area in search of these fossils.
The rocks on the east side of Dinosaur Ridge are part of the Cretaceous Dakota Formation. When Alameda Parkway was being constructed in 1937 to provide access to Red Rocks Park, workers discovered hundreds of dinosaur footprints. These were found to include mostly "Iguanodon"-like footprints. Carnivorous theropod tracks are also present.
The site features the Dinosaur Ridge Exhibit Hall with displays about the dinosaurs found at the site. Additionally, Dinosaur Ridge has interpretive signs at trail locations that explain the local geology, a volcanic ash bed, trace fossils, paleo-ecology, economic development of coal, oil and clay, and many other geologic and paleontological features.
Galaxy Nexus
The Galaxy Nexus is a smartphone made by Google and Samsung, using the Android operating system. The phone started being sold on November 17, 2011.
The Galaxy Nexus is designed to be a developer-friendly phone. It is very easy to unlock and root. To unlock the bootloader, boot the phone into fastboot mode by holding down both volume keys while powering the phone on, and connect the phone to a computer with the Android SDK installed and run the command "fastboot oem unlock". This is in contrast to most other mobile phones which are designed to be difficult to unlock. This phone uses NFC, which allows it to communicate wirelessly with other Android devices.
Nexus
Nexus might mean:
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