U.S. Route 20
U. S. Route 20 is an east–west United States highway. The 0 in its number indicates that US20 is a coast-to-coast route. Spanning 3,365 miles, it is the longest road in the United States, there is a discontinuity in the official designation of US20 through Yellowstone National Park, with unnumbered roads used to traverse the park. It and US30 break the general U. S. Route numbering rules in Oregon, since US30 actually starts north of US20, the two overlap and continue in the correct positioning near Caldwell, Idaho. This is because US20 was not a planned coast-to-coast route while US30 was, US20 originally ended at the eastern entrance of Yellowstone Park, it was extended in 1940. The highways eastern terminus is in Boston, Massachusetts, at Kenmore Square and its western terminus is in Newport, Oregon, at an intersection with US101, within a mile of the Pacific Ocean. The highway passes through the states, US20 begins at an intersection with US101 in Newport, Oregon. It eventually overlaps with US26 in Vale, and the two roads continue concurrently to the Idaho border, US20 crosses into Idaho from Oregon northwest of Parma.
It runs concurrently with US26 and joins US95 through Parma, US 20/US26 leaves US95 southeast of Parma and runs to Caldwell where US 20/US26 joins with I-84 and US30 for a short time. It continues into and across Camas County through Fairfield to Timmerman Junction, the intersection in Blaine County with State Highway 75, the route to Sun Valley, Galena Summit, and Stanley. US20 continues east through Picabo and Carey, joined with US26 and US93, to Craters of the Moon and Arco, where US93 splits off and turns north-northwest to climb the Big Lost River valley. US20 climbs through the communities of St. Anthony and Island Park, in the state of Montana, US20 runs for less than 10 miles. It runs from the Idaho state line to West Yellowstone, Montana, US20 is known as the Targhee Pass Highway in Montana. In the state of Wyoming, the segment of US20 starts at the eastern entrance to Yellowstone National Park along with the western termini of US14. These three routes run east to Greybull, where US14 continues east and US 16/US20 turns south, at Worland, US20 joins US26 in Shoshoni, where it turns east.
In Casper it joins I-25 and US87 and these four routes stay combined to Orin, where US20 turns east. At its intersection with I-25, US18 begins, US18 and US20 are concurrent from Orin to Lusk. US18 separates there and US20 runs east into Nebraska, in the state of Nebraska, US20 runs from west of Harrison to South Sioux City on the Missouri River
A rock shelter is a shallow cave-like opening at the base of a bluff or cliff. In arid areas, wind erosion can be an important factor in rockhouse formation, erosion from moving water is seldom a significant factor. Many rock shelters are found under waterfalls, Rock shelter formation types Rock shelters are often important archaeologically. Because rock shelters form natural shelters from the weather, prehistoric humans often used them as living-places, and left behind debris, tools, in mountainous areas the shelters can be important for mountaineers. In western Connecticut and eastern New York, many shelters are known by the colloquialism leatherman caves. Sandstone can be used as shingles for roof tops when possible, the Cumberland stitchwort is an endangered species of plant which is found only in rock shelters in Kentucky and Tennessee. Gatecliff Rockshelter Kinlock Shelter Mesa Verde Overhang Roc-aux-Sorciers Shelter Rock Walnut Canyon
Some authorities restrict the use of the term to bodies deliberately embalmed with chemicals, but the use of the word to cover accidentally desiccated bodies goes back to at least 1615 CE. Mummies of humans and other animals have found on every continent. Over one million animal mummies have been found in Egypt, many of which are cats, in addition to the well-known mummies of ancient Egypt, deliberate mummification was a feature of several ancient cultures in areas of America and Asia with very dry climates. The Spirit Cave mummies of Fallon, Nevada in North America were accurately dated at more than 9,400 years old. Before this discovery, the oldest known deliberate mummy was a child, one of the Chinchorro mummies found in the Camarones Valley, which dates around 5050 BCE. The oldest known naturally mummified corpse is a severed head dated as 6,000 years old. These substances were defined as mummia, the OED defines a mummy as the body of a human being or animal embalmed as a preparation for burial, citing sources from 1615 CE onward.
However, Chambers Cyclopædia and the Victorian zoologist Francis Trevelyan Buckland define a mummy as follows, applied to the frozen carcase of an animal imbedded in prehistoric snow. Wasps of the genus Aleiodes are known as mummy wasps because they wrap their prey as mummies. While interest in the study of mummies dates as far back as Ptolemaic Greece, prior to this, many rediscovered mummies were sold as curiosities or for use in pseudoscientific novelties such as mummia. The first modern scientific examinations of mummies began in 1901, conducted by professors at the English-language Government School of Medicine in Cairo, Egypt. The first X-ray of a mummy came in 1903, when professors Grafton Elliot Smith, British chemist Alfred Lucas applied chemical analyses to Egyptian mummies during this same period, which returned many results about the types of substances used in embalming. Lucas made significant contributions to the analysis of Tutankhamun in 1922, pathological study of mummies saw varying levels of popularity throughout the 20th century.
In 1992, the First World Congress on Mummy Studies was held in Puerto de la Cruz on Tenerife in the Canary Islands, more than 300 scientists attended the Congress to share nearly 100 years of collected data on mummies. This was not possible prior to the Congress due to the unique, in more recent years, CT scanning has become an invaluable tool in the study of mummification by allowing researchers to digitally unwrap mummies without risking damage to the body. The level of detail in such scans is so intricate that small linens used in areas such as the nostrils can be digitally reconstructed in 3-D. Such modelling has been utilized to perform autopsies on mummies to determine cause of death and lifestyle. Mummies are typically divided into one of two categories, anthropogenic or spontaneous
In archaeological terms, a projectile point is an object that was hafted to a projectile, such as a spear, dart, or arrow, or perhaps used as a knife. Scientific techniques exist to track the specific kinds of rock or minerals used to make stone tools in various regions back to their original sources. Occasionally, projectile points made of worked bone or ivory are found at archaeological sites, in regions where metallurgy had emerged, projectile points were made from copper, bronze, or iron. In North America, some late prehistoric points were fashioned from copper that was mined in the Lake Superior region, a large variety of prehistoric arrowheads, dart points, and spear points have been discovered. Flint, obsidian and many rocks and minerals were commonly used to make points in North America. Some of the more famous Paleo-Indian types include Clovis, projectile points fall into two general types, dart/spear points, and arrow points. Larger points were used to tip spears and atlatl darts, arrow points are smaller and lighter than dart points, and were used to tip arrows.
The question of how to distinguish an arrow point from a point used on a projectile is non-trivial. According to some investigators, the best indication is the width of the hafting area, an alternative approach is to distinguish arrow points by their necessarily smaller size. Projectile points come in a variety of shapes and styles, which vary according to chronological periods, cultural identities. Typological studies of projectile points have become more elaborate through the years, for instance, Gregory Perino began his categorical study of projectile point typology in the late 1950s. Collaborating with Robert Bell, he published a set of four volumes defining the known point types of that time, Perino followed this several years with a three-volume study of Selected Preforms and Knives of the North American Indians. Another recent set of studies of North American projectile points has been produced by Noel Justice
Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power.
The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations.
In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
The Shoshone River is a 100-mile long river in northern Wyoming in the United States. Its headwaters are in the Absaroka Range in Shoshone National Forest and it ends when it runs into the Big Horn River near Lovell, Wyoming. Cities it runs near or through are Cody, Byron, near Cody, it runs through a volcanically active region of fumaroles known as Colters Hell. This contributed to the river being named on old maps of Wyoming as the Stinking Water River, the current name was established in 1901 due to popular demand. West of Cody the river is impounded in Shoshone Canyon by the Buffalo Bill Dam, created as part of the Shoshone project, a number of hot springs along the Shoshone were drowned by the reservoir. Mummy Cave, an alcove eroded into a face by the North Fork of the Shoshone that has yielded evidence of 9000 years of occupation Shoshonite
The bighorn sheep is a species of sheep native to North America named for its large horns. These horns can weigh up to 14 kilograms, while the sheep themselves weigh up to 140 kg, recent genetic testing indicates three distinct subspecies of Ovis canadensis, one of which is endangered, O. c. sierrae. By 1900, the population had crashed to several thousand, due to diseases introduced through European livestock, divergence from their closest Asian ancestor occurred about 600,000 years ago. In North America, wild sheep diverged into two extant species—Dall sheep, which occupy Alaska and northwestern Canada, and bighorn sheep, which range from southern Canada to Mexico. However, the status of species is questionable given that hybridization has occurred between them in their recent evolutionary history. This subspecies has been extinct since 1925, California bighorn sheep, O. c. californiana, are found from British Columbia south to California and east to North Dakota. The definition of this subspecies has been updated, nelsons bighorn sheep, O. c.
nelsoni, the most common desert bighorn sheep, ranges from California through Arizona. Mexican bighorn sheep, O. c. mexicana, range from Arizona and New Mexico south to Sonora and Chihuahua. Peninsular bighorn sheep O. c. cremnobates, occur in the Peninsular Ranges of California and Baja California Rocky Mountain bighorn sheep, weems bighorn sheep, O. c. weemsi, are found in Baja California. However, starting in 1993, Ramey and colleagues, using DNA testing, have shown this division into seven subspecies is largely illusory, most scientists currently recognize three subspecies of bighorn. Thus the three subspecies of Ovis canadensis, Rocky Mountain bighorn sheep – occupying the U. S. and Canadian Rocky Mountains, Sierra Nevada bighorn sheep – formerly California bighorn sheep, a genetically distinct subspecies that only occurs in the Sierra Nevada in California. However, historic observer records suggest that bighorn sheep may have ranged as far west as the California Coastal Ranges which are contiguous to the Sierra Nevada via the Transverse Ranges.
An account of sheep in the vicinity of the Mission San Antonio near Jolon, California. Desert bighorn sheep – occurring throughout the regions of the Southwestern United States. The 2016 genetics study suggested more modest divergence of this desert bighorn sheep into three lineages consistent with the work of Cowan, Nelson and Peninsular. These three lineages occupy desert biomes that vary significantly in climate, suggesting exposure to different selection regimes, Bighorn sheep are named for the large, curved horns borne by the rams. Ewes have horns, but they are shorter with less curvature and they range in color from light brown to grayish or dark, chocolate brown, with a white rump and lining on the backs of all four legs. Males typically weigh 58–143 kg, are 90–105 cm tall at the shoulder, females are typically 34–91 kg, 75–90 cm tall, and 1. 28–1.58 m long
Nebraska /nᵻˈbræskə/ is a state that lies in both the Great Plains and the Midwestern United States. Its area is just over 77,220 sq mi with almost 1.9 million people and its largest city is Omaha, which is on the Missouri River. The state is crossed by many trails and was explored by the Lewis. Nebraska was admitted as the 37th state of the United States in 1867 and it is the only state in the United States whose legislature is unicameral and officially nonpartisan. Nebraska is composed of two major regions, the Dissected Till Plains and the Great Plains. The Dissected Till Plains is a region of rolling hills. The Great Plains occupy most of western Nebraska, characterized by treeless prairie, the state has a large agriculture sector and is a major producer of beef, pork and soybeans. Two major climatic zones are represented in Nebraska, the half of the state has a humid continental climate, and the western half. Indigenous peoples lived in the region of present-day Nebraska for thousands of years before European exploration.
The historic tribes in the state included the Omaha, Ponca, Otoe, when European exploration and settlement began, both Spain and France sought to control the region. In the 1690s, Spain established trade connections with the Apaches, by 1703, France had developed a regular trade with the native peoples along the Missouri River in Nebraska, and by 1719 had signed treaties with several of these peoples. After war broke out between the two countries, Spain dispatched an expedition to Nebraska under Lieutenant General Pedro de Villasur in 1720. The party was attacked and destroyed near present-day Columbus by a force of Pawnees and Otoes. The massacre of the Villasur expedition effectively put an end to Spanish exploration of Nebraska for the remainder of the 18th century, in 1762, during the Seven Years War, France ceded the Louisiana territory to Spain. Frances withdrawal from the area left Britain and Spain competing for dominance along the Mississippi, by 1773, that year, Mackays party built a trading post, dubbed Fort Carlos IV, near present-day Homer.
In 1819, the United States established Fort Atkinson as the first U. S. Army post west of the Missouri River, the army abandoned the fort in 1827 as migration moved further west. European-American settlement did not begin in any numbers until after 1848, on May 30,1854, the US Congress created the Kansas and the Nebraska territories, divided by the Parallel 40° North, under the Kansas–Nebraska Act. The Nebraska Territory included parts of the current states of Colorado, North Dakota, South Dakota, the territorial capital of Nebraska was Omaha
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is compacted into a rock in a process called consolidation. Tuff is sometimes called tufa, particularly used as construction material. Rock that contains greater than 50% tuff is considered tuffaceous, Tuff is a relatively soft rock, so it has been used for construction since ancient times. Since it is common in Italy the Romans used it often for construction, the Rapa Nui people used it to make most of the moai statues in Easter Island. Tuff can be classified as either sedimentary or igneous rocks and they are usually studied in the context of igneous petrology, although they are sometimes described using sedimentological terms. The material that is expelled in a volcanic eruption can be classified into three types, Volcanic gases, a mixture mostly of water vapour, carbon dioxide. Lava, the name of magma when it emerges and flows over the surface, and tephra, chunks of solid material of all shapes and sizes ejected and thrown through the air.
Tephra is made when magma inside the volcano is blown apart by the expansion of hot volcanic gases. It is common for magma to explode as the gas dissolved in it comes out of solution as the pressure decreases when it flows to the surface and these violent explosions produce solid chunks of material that can fly from the volcano. When these chunks are smaller than 2 mm in diameter they are called volcanic ash and it is made of small, slaggy pieces of lava and rock that have been tossed into the air by outbursts of steam and other gases. Among the loose beds of ash that cover the slopes of many volcanoes, in addition to true ashes of the kind described above, there are lumps of the old lavas and tuffs forming the walls of the crater, etc. In some great volcanic explosions nothing but materials of the kind were emitted. The ashes vary in size from large blocks twenty feet or more in diameter to the minutest impalpable dust, the large masses are called volcanic bombs, they have mostly a rounded, elliptical or pear-shaped form owing to rotation in the air before they solidified.
Many of them have ribbed or nodular surfaces, and sometimes they have a crust intersected by many cracks like the surface of a loaf of bread, any ash in which they are very abundant is called an agglomerate. But many volcanoes stand near the sea, and the ashes cast out by them are mingled with the sediments that are gathering at the bottom of the waters, in this way ashy muds or sands or even in some cases ashy limestones are being formed. As a matter of fact most of the found in the older formations contain admixtures of clay and sometimes fossil shells. The showers of ashes often follow one another after longer or shorter intervals, the coarsest materials or agglomerates show this least distinctly, in the fine beds it is often developed in great perfection
A concurrency in a road network is an instance of one physical road bearing two or more different highway, motorway, or other route numbers. When two freeways share the same right-of-way, it is called a common section or commons. Other terminology for a concurrency includes overlap, duplex, multiplex, concurrent numbering can become very common in countries that allow it. In some countries, concurrent numbering is avoided by posting only one number on road signs. Criticism of concurrencies include environmental intrusion, as well as being considered a factor in road accidents, most concurrencies are simply a combination of two route numbers on the same physical road. This is often advantageous as well as economically advantageous, it may be better for two route numbers to be combined into one along riverways or through mountain valleys. Some nations allow for concurrencies to occur, some nations specifically do not allow it to happen, in those nations which do permit concurrencies, it can become very common.
In these countries, there are a variety of concurrences which can occur, an example of this is the concurrency of I-70 and I-76 on the Pennsylvania Turnpike in western Pennsylvania. A triple Interstate concurrency is found north of Madison, with I-39, I-90, Wisconsin has another triple Interstate concurrency along the five-mile section of I-41, I-43, and I-894 in Milwaukee, Wisconsin. The concurrency of I-41 and I-43 on this roadway is an example of a wrong-way concurrency, the longest Interstate highway concurrency is I-80 and I-90 for 265 miles across Indiana and Ohio. There are examples of eight-way concurrencies, I-465 around Indianapolis and Georgia State Route 10 Loop around downtown Athens, Georgia. Portions of the 53-mile I-465 overlap with I-74, US31, US36, US40, US52, US421, SR37, seven of the eight other designations overlap between exits 46 and 47 to create an eight-way concurrency. In the United States, concurrencies are simply marked by placing signs for both routes on the same or adjacent posts, the federal Manual on Uniform Traffic Control Devices prescribes that when mounting these adjacent signs together that the numbers will be arranged vertically or horizontally in order of precedence.
The order to be used is Interstate Highways, U. S. Highways, state highways, and finally county roads, several states do not officially have any concurrencies, instead officially ending routes on each side of one. There are several circumstances where unusual concurrencies exist along state borders, one example occurs along the Oklahoma–Arkansas state line. At the northern end of this border Oklahoma State Highway 20 runs concurrently with Arkansas Highway 43, concurrencies are found in Canada. In Manitoba, the Trans-Canada Highway from Winnipeg to Portage la Prairie is concurrently signed with Yellowhead Highway, in Ontario, the Queen Elizabeth Way and Highway 403 run concurrently between Burlington and Oakville, forming the provinces only concurrency between two 400-series highways. In the United Kingdom, routes do not run concurrently with others, where this would normally occur, the roadway takes the number of only one of the routes, while the other routes are considered to have a gap and are signed in brackets
An alluvial fan is a fan- or cone-shaped deposit of sediment crossed and built up by streams. If a fan is built up by debris flows it is called a debris cone or colluvial fan. These flows come from a point source at the apex of the fan. Fans are typically found where a canyon draining from mountainous terrain emerges out onto a flatter plain, a convergence of neighboring alluvial fans into a single apron of deposits against a slope is called a bajada, or compound alluvial fan. As a streams gradient decreases, it drops coarse-grained material and this reduces the capacity of the channel and forces it to change direction and gradually build up a slightly mounded or shallow conical fan shape. The deposits are poorly sorted. There will be iso-transport energy lines forming concentric arcs about the point at the apex of the fan. Thus the material will tend to be deposited equally about these lines, Alluvial fans are often found in desert areas subject to periodic flash floods from nearby thunderstorms in local hills.
The typical watercourse in an arid climate has a large, funnel-shaped basin at the top, leading to a narrow defile, multiple braided streams are usually present and active during water flows. Phreatophytes are plants that are concentrated at the base of alluvial fans. They have long tap roots 30 to 50 feet to water that has seeped through the fan and hit an impermeable layer, sometimes collecting in springs. These stands of shrubs cling to the soil at their bases, Alluvial fans develop in wetter climates. Along the upper Koshi tributaries, tectonic forces elevate the Himalayas several millimeters annually, uplift is approximately in equilibrium with erosion, so the river annually carries some 100 million cubic meters of sediment as it exits the mountains. Deposition of this magnitude over millions of years is more than sufficient to account for the megafan, despite overpopulation on the plains, this bhabar zone is highly malarial and has remained largely uninhabited. In North America, streams flowing into Californias Central Valley have deposited smaller, such as that of the Kings River flowing out of the Sierra Nevada creates a low divide, turning the south end of the San Joaquin Valley into an endorheic basin without a connection to the ocean.
Alluvial fans are subject to flooding and can be more dangerous than the upstream canyons that feed them. Their slightly convex perpendicular surfaces cause water to spread widely until there is no zone of refuge, if the gradient is steep, active transport of materials down the fan creates a moving substrate that is inhospitable to travel on foot or wheels. But as the gradient diminishes downslope, water comes down from above faster than it can flow away downstream, in the case of the Koshi River, the huge sediment load and megafans slightly convex transverse surface conspire against engineering efforts to contain peak flows inside manmade embankments