The Siskiyou Trail stretched from Californias Central Valley to Oregons Willamette Valley, modern-day Interstate 5 follows this pioneer path. The HBC had established itself on the Columbia River, and built Fort Vancouver, HBC parties began to explore south toward California in 1825. Alexander McLeod led exploration and trapping parties south beginning in 1826, reaching the Klamath River in 1827, in 1829 he led the first HBC trapping expedition to the Sacramento Valley, which allowed expeditions to reach as far south as French Camp near todays Stockton. McLeods exploring and trapping expeditions essentially established the Siskiyou Trail, linking Fort Vancouver with the Sacramento Valley, at first it was known by names such as the California Brigade Trail and the Southern Party Trail. McLeod and other members of his parties reported that the Native Americans south of the Umpqua River, along the Klamath, although the 42nd parallel marked the northern border of Mexican California, the Mexicans knew little about the interior and the HBC trappers ranged south at will.
Other HBC trappers who made use of the Siskiyou Trail include Peter Skene Ogden. In 1834, Ewing Young brought a herd of horses and mules over the Siskiyou Trail from missions in California for sale at British and this monumental task, requiring nearly three months, helped widen and establish the trail thereby solidifying the new American settlements in Oregon. In 1841 an overland party of the United States Exploring Expedition came down the Siskiyou Trail with the first scientists, the California Gold Rush, beginning in 1848, ushered in dramatically increased use of the Siskiyou Trail. The discovery of gold in Siskiyou County and especially at Yreka, the terrain was so rugged over the mountains of the trail, that travel was restricted to mule trains and horses. Early travelers were able to travel perhaps 20 miles in a day, stopping at wayside inns and hostels, such as at Portuguese Flat, Upper Soda Springs and Sisson, the first telegraph line connected early towns along the trail in 1864. Development accelerated with the arrival of the Central Pacific Railroad track completed in 1887, the historic route of the Siskiyou Trail extended from the Columbia District headquarters of the Hudsons Bay Company, at Fort Vancouver in southern Washington, to the San Francisco Bay Area.
In California the trail went through or near modern-day Redding, Dunsmuir, in Oregon the route went through or near modern-day Ashland, Grants Pass, Eugene and Portland. The trail crested at the Siskiyou Summit just north of the Oregon-California border, between 1869 and 1887, the Oregon & California Railroad Company built a railroad along this route, crossing Siskiyou Summit in 1887. In the mid-1910s, the pioneering Pacific Highway, numbered as U. S. Highway 99, Interstate 5 was built in the 1960s along the route of the original 1820s Siskiyou Trail. About 4 miles north of the California border, and just south of Ashland, the highway crosses Siskiyou Summit, the railroad and interstate highway deviate from the original trail in small ways according to the needs and engineering available to their builders. Museum of the Siskiyou Trail Archaeological study of Trail Early goldmining along the Trail Stone Turnpike from Central Valley to Upper Soda Springs Early stagecoach use and railroad construction
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant, or other type of organism. The term typically refers to the zone in which the organism lives and it is the natural environment in which an organism lives, or the physical environment that surrounds a species population. Every organism has certain habitat needs for the conditions in which it will thrive, habitat types include polar, temperate and tropical. The terrestrial vegetation type may be forest, grassland, the word habitat has been in use since about 1755 and derives from the Latin third-person singular present indicative of habitāre, to inhabit, from habēre, to have or to hold. Habitat can be defined as the environment of an organism. It is similar in meaning to a biotope, an area of environmental conditions associated with a particular community of plants. Generally speaking, animal communities are reliant on specific types of plant communities, some plants and animals are generalists, and their habitat requirements are met in a wide range of locations.
The small white butterfly for example is found on all the continents of the world apart from Antarctica and its larvae feed on a wide range of Brassicas and various other plant species, and it thrives in any open location with diverse plant associations. Disturbance is important in the creation of biodiverse habitats, in the absence of disturbance, a climax vegetation cover develops that prevents the establishment of other species. Lightning strikes and toppled trees in tropical forests allow species richness to be maintained as pioneering species move in to fill the gaps created. Similarly coastal habitats can become dominated by kelp until the seabed is disturbed by a storm, another cause of disturbance is when an area may be overwhelmed by an invasive introduced species which is not kept under control by natural enemies in its new habitat. Terrestrial habitat types include forests, grasslands and deserts, within these broad biomes are more specific habitats with varying climate types, temperature regimes, soils and vegetation types.
Many of these habitats grade into each other and each one has its own communities of plants. A habitat may suit a particular species well, but its presence or absence at any particular location depends to some extent on chance, on its dispersal abilities, freshwater habitats include rivers, lakes, ponds and bogs. Although some organisms are found across most of these habitats, the majority have more specific requirements, aquatic plants can be floating, semi-submerged, submerged or grow in permanently or temporarily saturated soils besides bodies of water. Marine habitats include brackish water, bays, the sea, the intertidal zone. Further variations include rock pools, sand banks, brackish lagoons and pebbly beaches, the benthic zone or seabed provides a home for both static organisms, anchored to the substrate, and for a large range of organisms crawling on or burrowing into the surface. A desert is not the kind of habitat that favours the presence of amphibians, with their requirement for water to keep their skins moist, some frogs live in deserts, creating moist habitats underground and hibernating while conditions are adverse
In geography and geology, a cliff is a vertical, or nearly vertical, rock exposure. Cliffs are formed as erosion landforms by the processes of weathering, Cliffs are common on coasts, in mountainous areas and along rivers. Cliffs are usually formed by rock that is resistant to weathering, sedimentary rocks most likely to form cliffs include sandstone, limestone and dolomite. Igneous rocks such as granite and basalt often form cliffs, an escarpment is a type of cliff, formed by the movement of a geologic fault or a landslide. Most cliffs have some form of slope at their base. In arid areas or under high cliffs, they are generally exposed jumbles of fallen rock, in areas of higher moisture, a soil slope may obscure the talus. Many cliffs feature tributary waterfalls or rock shelters, sometimes a cliff peters out at the end of a ridge, with tea tables or other types of rock columns remaining. Coastal erosion may lead to the formation of sea cliffs along a receding coastline, the Ordnance Survey distinguishes between cliffs and outcrops.
Cliff is a Romance loanword that has its origins in the Latin forms clivus / clevus. Given that a cliff need not be vertical, there can be ambiguity about whether a given slope is a cliff or not. For example, given a vertical rock wall above a very steep slope. Listings of cliffs are thus inherently uncertain, some of the largest cliffs on Earth are found underwater. For example, an 8,000 m drop over a 4,250 m span can be found at a ridge sitting inside the Kermadec Trench. One candidate for highest cliff in the world is Nanga Parbats Rupal Face, according to other sources, the highest cliff in the world, about 1,340 m high, is the east face of Great Trango in the Karakoram mountains of northern Pakistan. The location of the worlds highest sea cliffs depends on the definition of cliff that is used, guinness World Records states it is Kalaupapa, Hawaii, at 1,010 m high. Another contender is the face of Mitre Peak, which drops 1,683 m to Milford Sound. These are subject to a less stringent definition, as the slope of these cliffs at Kaulapapa is about 1.7, corresponding to an angle of 60 degrees.
A more vertical drop into the sea can be found at Maujit Qaqarssuasia which is situated in the Torssukátak fjord area at the tip of South Greenland
Protected areas of the United States
The protected areas of the United States are managed by an array of different federal, state and local level authorities and receive widely varying levels of protection. Some areas are managed as wilderness, while others are operated with acceptable commercial exploitation, as of 2015, the 25,800 protected areas covered 1,294,476 km2, or 14 percent of the land area of the United States. This is one-tenth of the land area of the world. The U. S. had a total of 787 National Marine Protected Areas, covering an additional 1,271,408 km2, some areas are managed in concert between levels of government. The Father Marquette National Memorial is an example of a park operated by a state park system. As of 2007, according to the United Nations Environment Programme, federal level protected areas are managed by a variety of agencies, most of which are a part of the National Park Service, a bureau of the United States Department of the Interior. They are often considered the jewels of the protected areas.
Other areas are managed by the United States Forest Service, the Bureau of Land Management, the United States Army Corps of Engineers is claimed to provide 30 percent of the recreational opportunities on federal lands, mainly through lakes and waterways that they manage. The highest levels of protection, as described by the International Union for Conservation of Nature, are Level I, the United States maintains 12 percent of the Level I and II lands in the world. These lands had an area of 210,000 sq mi. A confusing system for naming protected areas results in some types being used by more than one agency, for instance, both the National Park Service and the U. S. Forest Service operate areas designated National Preserves and National Recreation Areas. The National Park Service, the U. S. Forest Service, National Wilderness Areas are designated within other protected areas, managed by various agencies and sometimes wilderness areas span areas managed by multiple agencies. States and local zoning bodies may or may not choose to protect these, the state of Colorado, for example, is very clear that it does not set any limits on owners of NRHP properties.
State parks vary widely from urban parks to large parks that are on a par with national parks. Some state parks, like Adirondack Park, are similar to the National parks of England and Wales, about half the area of the park, some 3,000,000 acres, is state-owned and preserved as forever wild by the Forest Preserve of New York. Wood-Tikchik State Park in Alaska claims to be the largest state park by the amount of protected land, it is larger than many U. S. National Parks. Many states operate game and recreation areas. S, State and tribal wilderness areas Various counties, metropolitan authorities, regional parks, soil conservation districts and other units manage a variety of local level parks. Some of these are more than picnic areas or playgrounds, however
California Coast Ranges
The Coast Ranges of California span 400 miles from Del Norte or Humboldt County, California south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains, physiographically, they are a section of the larger Pacific Border province, which in turn are part of the larger Pacific Mountain System physiographic division. UNESCO has included the California Coast Ranges Biosphere Reserve in its Man, the northern end of the California Coast Ranges overlap the southern end of the Klamath Mountains for approximately 80 miles on the west. They extend southward for more than 600 miles to where the coastline turns eastward along the Santa Barbara Channel, here the southern end meets the Los Angeles Transverse Ranges, or Sierras de los Angeles. The rocks themselves that comprise the mountains are of a great variety, most of the rocks were formed during the Tertiary and Jurassic periods. All of the range has been folded and faulted during several periods, the California Ranges had a high production of mercury following the discovery of gold in the Sierra Nevada.
In the Cache Creek Basin, Cenozoic cinnabar deposits near Clear Lake are the northernmost of a group of similar deposits associated with volcanism, during 1877, these deposits hit their peak production of mercury, producing approximately 2,776 metric tons. These abandoned mines are still a source of mine waste runoff in Cache Creek, the Northern Coast Ranges are a section of the California Coast Ranges. They run parallel to the Pacific Coast from the North San Francisco Bay Area to coastal Del Norte County, the Klamath Mountains, including the Siskiyou Mountains sub-range, lie to the north and northeast. The Southern Coast Ranges lie to the south, the Northern Coast Ranges run north-south parallel to the coast. Component ranges within the Northern Coast Ranges include the Mendocino Range of western Mendocino County and the Mayacamas and Vaca Mountains and they include the King Range, which meet the sea in the Lost Coast region. The southernmost peak of the Northern Coast Ranges is Mount Tamalpais, the highest point in the Northern Coast Ranges is Mount Linn, at 8,098 ft.
The Northern Coast Ranges consist of two parallel belts of mountains, the Outer Northern Coast Ranges lying along the coast. They are separated by a system of valleys. The northern valley portion is drained by the Eel River and its tributaries, a series of short rivers, including the Mattole and Navarro rivers, drain the western slopes of the ranges. The eastern slopes of the drain into the Sacramento Valley. Clear Lake lies in the southeast portion of the range, U. S. Route 101 runs generally north-south in the valleys between the Outer and Inner Northern Coast Ranges. The seaward face of the coastal Outer Northern Coast Ranges is part of the Northern California coastal forests ecoregion, home to forests of Coast Redwood
Granite is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be white, pink, or gray in color. The word granite comes from the Latin granum, a grain, in reference to the structure of such a holocrystalline rock. By definition, granite is a rock with at least 20% quartz. The term granitic means granite-like and is applied to granite and a group of igneous rocks with similar textures and slight variations in composition. Occasionally some individual crystals are larger than the groundmass, in case the texture is known as porphyritic. A granitic rock with a texture is known as a granite porphyry. Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks, petrographic examination is required for identification of specific types of granitoids. The extrusive igneous rock equivalent of granite is rhyolite, Granite is nearly always massive and tough, and therefore it has gained widespread use throughout human history, and more recently as a construction stone.
The average density of granite is between 2.65 and 2.75 g/cm3, its compressive strength usually lies above 200 MPa, and its viscosity near STP is 3–6 •1019 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C, it is reduced in the presence of water. Granite has poor primary permeability, but strong secondary permeability, true granite according to modern petrologic convention contains both plagioclase and alkali feldspars. When a granitoid is devoid or nearly devoid of plagioclase, the rock is referred to as alkali feldspar granite, when a granitoid contains less than 10% orthoclase, it is called tonalite and amphibole are common in tonalite. A granite containing both muscovite and biotite micas is called a binary or two-mica granite, two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites. A worldwide average of the composition of granite, by weight percent, based on 2485 analyses. Much of it was intruded during the Precambrian age, it is the most abundant basement rock that underlies the relatively thin veneer of the continents.
Outcrops of granite tend to form tors and rounded massifs, granites sometimes occur in circular depressions surrounded by a range of hills, formed by the metamorphic aureole or hornfels. Granite often occurs as small, less than 100 km² stock masses
National Park Service
It was created on August 25,1916, by Congress through the National Park Service Organic Act and is an agency of the United States Department of the Interior. As of 2014, the NPS employs 21,651 employees who oversee 417 units, the National Park Service celebrated its centennial in 2016. National parks and national monuments in the United States were originally individually managed under the auspices of the Department of the Interior, the movement for an independent agency to oversee these federal lands was spearheaded by business magnate and conservationist Stephen Mather, as well as J. Horace McFarland. With the help of journalist Robert Sterling Yard, Mather ran a publicity campaign for the Department of the Interior and they wrote numerous articles that praised the scenic and historic qualities of the parks and their possibilities for educational and recreational benefits. This campaign resulted in the creation of a National Park Service, Mather became the first director of the newly formed NPS.
On March 3,1933, President Herbert Hoover signed the Reorganization Act of 1933, the act would allow the President to reorganize the executive branch of the United States government. It wasnt until that summer when the new President, Franklin D. Roosevelt, President Roosevelt agreed and issued two Executive orders to make it happen. In 1951, Conrad Wirth became director of the National Park Service, the demand for parks after the end of the World War II had left the parks overburdened with demands that could not be met. In 1952, with the support of President Dwight D. Eisenhower, he began Mission 66, New parks were added to preserve unique resources and existing park facilities were upgraded and expanded. In 1966, as the Park Service turned 50 years old, emphasis began to turn from just saving great and wonderful scenery, Director George Hartzog began the process with the creation of the National Lakeshores and National Recreation Areas. Since its inception in 1916, the National Park Service has managed each of the United States national parks, Yellowstone National Park was the first national park in the United States.
In 1872, there was no government to manage it. Yosemite National Park began as a park, the land for the park was donated by the federal government to the state of California in 1864 for perpetual conservation. Yosemite was returned to federal ownership, at first, each national park was managed independently, with varying degrees of success. In Yellowstone, the staff was replaced by the U. S. Army in 1886. Due to the irregularities in managing these national treasures, Stephen Mather petitioned the government to improve the situation. In response, Secretary of the Interior Franklin K. Lane challenged him to lobby for creating a new agency, Mather was successful with the ratification of the National Park Service Organic Act in 1916. Later, the agency was given authority over other protected areas, the National Park System includes all properties managed by the National Park Service
International Standard Book Number
The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, this can be rectified later. Another identifier, the International Standard Serial Number, identifies periodical publications such as magazines, the ISBN configuration of recognition was generated in 1967 in the United Kingdom by David Whitaker and in 1968 in the US by Emery Koltay.
The 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108, the United Kingdom continued to use the 9-digit SBN code until 1974. The ISO on-line facility only refers back to 1978, an SBN may be converted to an ISBN by prefixing the digit 0. For example, the edition of Mr. J. G. Reeder Returns, published by Hodder in 1965, has SBN340013818 -340 indicating the publisher,01381 their serial number. This can be converted to ISBN 0-340-01381-8, the check digit does not need to be re-calculated, since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with Bookland European Article Number EAN-13s. An ISBN is assigned to each edition and variation of a book, for example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, a 13-digit ISBN can be separated into its parts, and when this is done it is customary to separate the parts with hyphens or spaces.
Separating the parts of a 10-digit ISBN is done with either hyphens or spaces, figuring out how to correctly separate a given ISBN number is complicated, because most of the parts do not use a fixed number of digits. ISBN issuance is country-specific, in that ISBNs are issued by the ISBN registration agency that is responsible for country or territory regardless of the publication language. Some ISBN registration agencies are based in national libraries or within ministries of culture, in other cases, the ISBN registration service is provided by organisations such as bibliographic data providers that are not government funded. In Canada, ISBNs are issued at no cost with the purpose of encouraging Canadian culture. In the United Kingdom, United States, and some countries, where the service is provided by non-government-funded organisations. Australia, ISBNs are issued by the library services agency Thorpe-Bowker
Castle Crags Wilderness
The Castle Crags Wilderness is a 12, 232-acre wilderness area in the Castle Crags rock formations of the Trinity Mountains, and within the Shasta-Trinity National Forest, in northwestern California. It is located in Siskiyou County and Shasta County,40 miles north of Redding, the US Congress passsd the California Wilderness Act in 1984 which set aside the wilderness. Elevations of the Castle Crags range from 2, 500–7,300 feet, the Trinity Mountains are a range in the Klamath Mountains System and the Klamath geological province. The prominent spires in the southeast that make up the Castle Crags are the main attraction and are similar to the rock landscape in parts of Yosemite National Park. In the northern portion of the wilderness, the landscape is more like the Klamath Mountains with glacial erosion, several cirques, and abundant rainfall with a high, east-trending divide. The area is bounded on the east by the Sacramento River, in the north by the South Fork Sacramento River and in the south by the canyon of Castle Creek and the boundary of Castle Crags State Park.
One roadless area of 1,732 acres borders on the northwest and contains the largest glacial cirque, Castle Lake, now a historical landmark, the battle was fought on a ridge saddle between the lake and what is known as Battle Rock. The railroad touted the beauty of the West to increase ridership, improve the Wests image, with every slight change in the position of the beholder they seem to march and countermarch and recede, until one is ready to believe them moving. The advent of logging and mining brought even more people to the area with mining continuing until the 1950s. In 1933, concerned citizens worked to protect the area and were able to acquire much of the land that became the state park. President Reagan signed into law the California Wilderness Act in 1984 that protected another 10,500 acres and was added to the National Wilderness Preservation System. The wilderness contains more than 300 species of wildflowers, including the Castle Crags harebell, drier locations have yarrow and buckwheat.
Forested areas have incense cedar, white fir, ponderosa pine, several types of oaks with Pacific dogwood and brushlands have various kinds of manzanita along with huckleberry oak and mountain whitethorn. Poison oak is common, as are rattlesnakes—dictating caution when hiking the trails, black bears, coyotes and mountain lions are some of the larger predators in this diverse habitat of bare granite, steep slopes and mountain streams. The state park extends 480 acres inside the wilderness and has five of the nine trailheads, the Pacific Crest Trail traverses the wilderness for 19 miles with several spur trails connecting from the park to the PCT. The Castle Dome Trail is a hiking trail into the crags proper and passes near Indian Springs. Rock climbing opportunities range from Class 5 to Class 5. 13a in difficulty, the Forest Service encourages the use of Leave No Trace principles of outdoor travel to minimize impact to the environment. Trinity Mountains topics Flora of the Klamath Mountains Adkinson, Ron Wild Northern California, the Globe Pequot Press,2001 ISBN 1-56044-781-8 Shasta-Trinity National Forest and endemic plants in the forest retrieved 12-5-2008 Castle Crags Wilderness Area retrieved 12-5-2008
In anthropology, Achomawi are the northerly nine bands of the Pit River tribe of Native Americans who lived in what is now northeastern California in the United States. These nine autonomous bands of the Pit River Indians spoke various dialects of one language. The name Achomawi means river dwelling and the band historically inhabited the Fall River Valley, the other eight bands that shared the Achomawi language had a historic homeland located along other parts of the Pit River. Their territory extended from Big Bend to Goose Lake, estimates for the pre-contact populations of most native groups in California have varied substantially. Alfred L. Kroeber estimated the combined 1770 population of the Achomawi and Atsugewi as 3,000, a more detailed analysis by Fred B. Kniffen arrived at the same figure, T. R. Garth estimated the Atsugewi population at a maximum of 850, which would leave at least 2,150 for the Achomawi. Kroeber estimated population of the Achomawi 1910 as 1,000, edward S. Curtis, a photographer and author in the 1920s, gave a 1910 population of Achomawi at 984.
The Achomawi population was estimated at 1,500 in 2000, each of the nine bands in the Achomawi language group had defined separate territories up and down the banks of the Pit River. Within their respective territories, each band had several villages, which were composed of extended family members. The bands were organized by having one village with smaller satellite villages. The lower Pit River bands existed in a densely forested mountain zone, while the upper Pit River bands had a drier sage brush. Their housing, food sources, and seasonal movements therefore varied, in the summer, the Achomawi band, and other upper Pit River bands usually lived in cone-shaped homes covered in tule-mat and spent time under shade or behind windbreaks of brush or mats. In the winter, larger houses were built, partially underground, these winter homes had wooden frames which supported a covering made of a mix of bark and tule. In marriage, the bridegroom lived in the home briefly. Eventually she would move him to his family. A patrilineal society, chiefdom was handed down to the eldest son, when children were born, the parents would were put into seclusion and had food restrictions while waiting for their babies umbilical cord to fall off.
If twins were born, one of them was killed at birth, Achomawi buried their dead in a flexed position, on the side, facing east and at times in baskets. They cremated those who died outside of the community, bringing the back for burial back home
The Sacramento River is the principal river of Northern California in the United States, and is the largest river in California. Rising in the Klamath Mountains, the river flows south for 400 miles before reaching the Sacramento–San Joaquin River Delta, the Sacramento and its wide natural floodplain were once abundant in fish and other aquatic creatures, notably one of the southernmost large runs of chinook salmon in North America. For about 12,000 years, humans have depended on the vast natural resources of the watershed, the river has provided a route for trade and travel since ancient times. Hundreds of tribes sharing regional customs and traditions inhabited the Sacramento Valley, the Spanish explorer Gabriel Moraga named the river Rio de los Sacramentos in 1808, shortened and anglicized into Sacramento. In the 19th century gold was discovered on a tributary of the Sacramento River, starting the California Gold Rush, overland trails such as the California Trail and Siskiyou Trail guided hundreds of thousands of people to the gold fields.
By the late part of the mining had ceased to be a major part of the economy. Many populous communities were established along the Sacramento River, including the capital of Sacramento. Intensive agriculture and mining contributed to pollution in the Sacramento River, since the 1950s the watershed has been intensely developed for water supply and the generation of hydroelectric power. Today, large dams impound the river and almost all of its major tributaries, the Sacramento is used heavily for irrigation and serves much of Central and Southern California through the canals of giant state and federal water projects. The Sacramento River originates in the mountains and plateaus of far northern California as three major waterways that flow into Shasta Lake, the Upper Sacramento River, McCloud River and Pit River. The Upper Sacramento begins near Mount Shasta, at the confluence of North, Middle and it flows east into a small reservoir, Lake Siskiyou, before turning south. The river flows through a canyon for about 60 miles, past Dunsmuir and Castella, the Pit River, by far the largest of the three, begins in Modoc County in the northeastern corner of California.
Draining a vast and remote volcanic highlands area, it flows southwest for nearly 300 miles before emptying into Shasta Lake near Montgomery Creek, Goose Lake, straddling the Oregon–California border, occasionally overflows into the Pit River during wet years, although this has not happened since 1881. The Goose Lake watershed is the part of the Sacramento River basin extending into another state. Unlike most California rivers, the Pit and the McCloud Rivers are predominantly spring-fed, ensuring a large, at the lower end of Shasta Lake is Shasta Dam, which impounds the Sacramento River for flood control and hydropower generation. Before the construction of Shasta Dam the McCloud River emptied into the Pit River, the Pit River Bridge, which carries Interstate 5 and the Union Pacific Railroad over the reservoir, is structurally the highest double-decked bridge in the United States. The Upper Sacramento River canyon provides the route for I-5, below Shasta Dam the Sacramento River enters the foothills region of the northern Sacramento Valley.
It flows through Keswick Dam, where it receives about 1,200,000 acre feet of water per year diverted from the Trinity River and it swings east through Redding, the largest city of the Shasta Cascade region, and turns southeast, entering Tehama County
The Jurassic is a geologic period and system that spans 56.3 million years from the end of the Triassic Period 201.3 million years ago to the beginning of the Cretaceous Period 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era, known as the Age of Reptiles, the start of the period is marked by the major Triassic–Jurassic extinction event. The Jurassic is named after the Jura Mountains within the European Alps, by the beginning of the Jurassic, the supercontinent Pangaea had begun rifting into two landmasses, Laurasia to the north and Gondwana to the south. This created more coastlines and shifted the continental climate from dry to humid, on land, the fauna transitioned from the Triassic fauna, dominated by both dinosauromorph and crocodylomorph archosaurs, to one dominated by dinosaurs alone. The first birds appeared during the Jurassic, having evolved from a branch of theropod dinosaurs, other major events include the appearance of the earliest lizards, and the evolution of therian mammals, including primitive placentals.
Crocodilians made the transition from a terrestrial to a mode of life. The oceans were inhabited by marine reptiles such as ichthyosaurs and plesiosaurs, the chronostratigraphic term Jurassic is directly linked to the Jura Mountains. The name Jura is derived from the Celtic root jor, which was Latinised into juria, the Jurassic period is divided into the Early Jurassic and Late Jurassic epochs. The Jurassic System, in stratigraphy, is divided into the Lower Jurassic, the separation of the term Jurassic into three sections goes back to Leopold von Buch. The Jurassic North Atlantic Ocean was relatively narrow, while the South Atlantic did not open until the following Cretaceous period, the Tethys Sea closed, and the Neotethys basin appeared. Climates were warm, with no evidence of glaciation, as in the Triassic, there was apparently no land over either pole, and no extensive ice caps existed. In contrast, the North American Jurassic record is the poorest of the Mesozoic, the Jurassic was a time of calcite sea geochemistry in which low-magnesium calcite was the primary inorganic marine precipitate of calcium carbonate.
Carbonate hardgrounds were thus very common, along with calcitic ooids, calcitic cements, the first of several massive batholiths were emplaced in the northern American cordillera beginning in the mid-Jurassic, marking the Nevadan orogeny. Important Jurassic exposures are found in Russia, South America, Australasia. As the Jurassic proceeded and more groups of dinosaurs like sauropods and ornithopods proliferated in Africa. Middle Jurassic strata are well represented nor well studied in Africa. Late Jurassic strata are poorly represented apart from the spectacular Tendaguru fauna in Tanzania, the Late Jurassic life of Tendaguru is very similar to that found in western North Americas Morrison Formation. During the Jurassic period, the primary living in the sea were fish