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106-582: The Anaheim Bay entrance is located at the westernmost corner of Orange County near the Los Angeles County line. The bay and its associated harbors and wetlands extend southeast along the coast for a distance of some 7 miles (11 km) from Seal Beach towards Huntington Beach ; they are protected by a long peninsular barrier beach where Surfside , Sunset Beach and Bolsa Chica State Beach are situated. Los Alamitos Army Airfield and Naval Weapons Station Seal Beach are located adjacent to each other on

212-648: A 75-square-mile (190 km) watershed emptying directly into the bay. The Anaheim-Barber City Channel (also known as the Bolsa Chica Channel), 8.65 miles (13.92 km) long, begins in Anaheim and flows through Stanton , Garden Grove , Westminster and Seal Beach before emptying into the north end of the Anaheim Bay Marsh. The 7.91-mile (12.73 km) Westminster Channel drains parts of Garden Grove, Westminster, Huntington Beach and Seal Beach and joins with

318-591: A French ship carrying supplies for the Mexicans. During the American Civil War a Union artillery base was established here to defend the harbor against the Confederates. The Anaheim Lighter Company was established in 1868 with a 20-year concession, to operate Anaheim Harbor as a port. Cargo was delivered to the harbor from as far away as San Bernardino, California , Yuma, Arizona and Salt Lake City, Utah . In

424-585: A change from low-amplitude glacial cycles with a dominant periodicity of 41,000 years to asymmetric high-amplitude cycles dominated by a periodicity of 100,000 years. However, a 2020 study concluded that ice age terminations might have been influenced by obliquity since the Mid-Pleistocene Transition, which caused stronger summers in the Northern Hemisphere . Glaciation in the Pleistocene

530-574: A deviation from today's annual mean temperature, taken as zero. This sort of graph is based on another isotope ratio versus time. Ratios are converted to a percentage difference from the ratio found in standard mean ocean water (SMOW). The graph in either form appears as a waveform with overtones . One half of a period is a Marine isotopic stage (MIS). It indicates a glacial (below zero) or an interglacial (above zero). Overtones are stadials or interstadials. According to this evidence, Earth experienced 102 MIS stages beginning at about 2.588 Ma BP in

636-421: A few regions had been studied and the names were relatively few. Today the geologists of different nations are taking more of an interest in Pleistocene glaciology. As a consequence, the number of names is expanding rapidly and will continue to expand. Many of the advances and stadials remain unnamed. Also, the terrestrial evidence for some of them has been erased or obscured by larger ones, but evidence remains from

742-406: A large cluster of government buildings in the city's Civic Center. Historically, the courthouses were county-owned buildings that were maintained at county expense, which created significant friction since the trial court judges, as officials of the state government, had to lobby the county Board of Supervisors for facility renovations and upgrades. In turn, the state judiciary successfully persuaded

848-400: A median income of $ 36,299 versus $ 30,981 for females. The per capita income for the county was $ 20,683. There are 14.4% of families living below the poverty line and 17.9% of the population, including 24.2% of under 18 and 10.5% of those over 64. Los Angeles County has the highest number of millionaires of any county in the nation, totaling 261,081 households as of 2007. The homeownership rate

954-510: A single county. As a result, both the county superior court and the federal district court are respectively the busiest courts of their type in the nation. Many celebrities have been seen in Los Angeles courts. In 2003, the television show Extra (based in nearby Glendale ) found itself running so many reports on the legal problems of local celebrities that it spun them off into a separate show, Celebrity Justice . State cases are appealed to

1060-568: A team of Russian scientists in collaboration with Princeton University announced that they had brought two female nematodes frozen in permafrost , from around 42,000 years ago, back to life. The two nematodes, at the time, were the oldest confirmed living animals on the planet. The evolution of anatomically modern humans took place during the Pleistocene. At the beginning of the Pleistocene Paranthropus species were still present, as well as early human ancestors, but during

1166-648: A third jetty to the bay mouth, in order to separate the entrances for military vessels and pleasure craft. However the project was not implemented, in part due to fears that it would impact surf and cause harmful erosion to the local beaches. A modernization project began in 2019 that included dredging the turning basin in order to accommodate amphibious assault ships that are currently resupplied by helicopters off Marine Corps Air Station Camp Pendleton . The U.S. Environmental Protection Agency lists Anaheim Bay as an impaired waterbody, with high concentrations of dieldrin, nickel, PCBs and sediment toxicity. Huntington Harbor

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1272-550: Is 365,000 workers. Despite a business exodus from Downtown Los Angeles since the COVID-19 pandemic , the city's urban core is evolving as a cultural center with the world's largest showcase of architecture designed by Frank Gehry . The following major companies have headquarters in Los Angeles County: The Los Angeles County Office of Education provides a supporting role for school districts in

1378-400: Is 47.9%, and the median value for houses is $ 409,300. 42.2% of housing units are in multi-unit structures. Los Angeles County has the largest number of homeless people , with "48,000 people living on the streets, including 6,000 veterans ," in 2010. As of 2017 the number of homeless people in the county increased to nearly 58,000. In 2015, there were over two thousand Christian churches ,

1484-633: Is a state-mandated county transportation commission that also operates bus and rail. In the United States House of Representatives , Los Angeles County is split between 17 congressional districts. In the California State Senate , Los Angeles County is split between 13 legislative districts. In the California State Assembly , Los Angeles County is split between 24 legislative districts. On November 4, 2008, Los Angeles County

1590-532: Is also contaminated by chlordane , copper, lead, nickel, and PCBs. Urban runoff has also introduced high concentrations of pathogens such as E.coli into the bay. Los Angeles County, California Los Angeles County , officially the County of Los Angeles and sometimes abbreviated as L.A. County , is the most populous county in the United States , with 9,861,224 residents estimated in 2022. Its population

1696-576: Is connected to the inner deep water harbor by a channel 164 feet (50 m) wide and 13 feet (4.0 m) deep. To the north of Anaheim Bay is the Anaheim Salt Marsh in the Seal Beach National Wildlife Refuge , which consists of over 800 acres (320 ha) of predominantly salt marshes connected by tidal channels to the bay. About 131 acres (53 ha) of this is open water at high tide. The salt marsh also encloses Hog Island,

1802-765: Is estimated that, at maximum glacial extent, 30% of the Earth's surface was covered by ice. In addition, a zone of permafrost stretched southward from the edge of the glacial sheet, a few hundred kilometres in North America , and several hundred in Eurasia . The mean annual temperature at the edge of the ice was −6 °C (21 °F); at the edge of the permafrost, 0 °C (32 °F). Each glacial advance tied up huge volumes of water in continental ice sheets 1,500 to 3,000 metres (4,900–9,800 ft) thick, resulting in temporary sea-level drops of 100 metres (300 ft) or more over

1908-520: Is greater than that of 40 individual U.S. states . Comprising 88 incorporated cities and many unincorporated areas within a total area of 4,083 square miles (10,570 km ), it is home to more than a quarter of Californians and is one of the most ethnically diverse U.S. counties. The county's seat , Los Angeles , is the second most populous city in the United States , with 3,822,238 residents estimated in 2022. The county has been world-renowned as

2014-491: Is home to the largest Armenian population outside of Armenia. Los Angeles County contains the largest Iranian population outside of Iran of any other county or county equivalent globally. At the 2000 census, there were 9,519,338 people, 3,133,774 households, and 2,137,233 families in the county. The population density was 2,344 inhabitants per square mile (905/km ). There were 3,270,909 housing units at an average density of 806 units per square mile (311 units/km ). Of

2120-431: Is managed on a day-to-day basis by a chief executive officer and is organized into many departments, each of which is enormous in comparison to equivalent county-level (and even many state-level) departments anywhere else in the United States. Some of the larger or better-known departments include: The Los Angeles County Metropolitan Transportation Authority , despite its name, is not a County department. Technically it

2226-464: Is more arts-centered. Santa Monica's pier is a well known tourist spot, famous for its Ferris wheel and bumper car rides, which were featured in the introductory segment of the television sitcom Three's Company . Further north in Pacific Palisades one finds the beaches used in the television series Baywatch . The fabled Malibu , home of many film and television stars, lies west of it. In

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2332-413: Is natural but dredged to maintain a minimum depth of 13 feet (4.0 m). The two harbors are connected by a channel 436 feet (133 m) wide and 43 feet (13 m) deep. To the southeast is long, narrow Huntington Harbor, a residential marina of 153 acres (62 ha). Once a shallow tidal lagoon, Huntington Harbor is now dredged to a depth of 11 feet (3.4 m) to provide passage for small boats. It

2438-454: Is no systematic correspondence between pluvials to glacials, however. Moreover, regional pluvials do not correspond to each other globally. For example, some have used the term "Riss pluvial" in Egyptian contexts. Any coincidence is an accident of regional factors. Only a few of the names for pluvials in restricted regions have been stratigraphically defined. The sum of transient factors acting at

2544-505: Is the U.S. Supreme Court in Washington, D.C. The following table includes the number of incidents reported and the rate per 1,000 persons for each type of offense. Crime in 2013 According to the authors of Wild L.A. , a book about urban biodiversity, "Los Angeles is the birdiest county in the country with over 500 recorded species." L.A.'s amenable climate supports a large number of introduced, tropical and migratory species. Because of

2650-619: Is the largest diocese in the United States. In 2014, the county had 3,275 religious organizations, the most out of all US counties. The Government of Los Angeles County is defined and authorized under the California Constitution , California law and the Charter of the County of Los Angeles. Much of the Government of California is in practice the responsibility of local governments such as

2756-578: The Ice Age ) is the geological epoch that lasted from c.  2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations . Before a change was finally confirmed in 2009 by the International Union of Geological Sciences , the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of

2862-638: The Alpine ice sheet on the Alps . Scattered domes stretched across Siberia and the Arctic shelf. The northern seas were ice-covered. South of the ice sheets large lakes accumulated because outlets were blocked and the cooler air slowed evaporation. When the Laurentide Ice Sheet retreated, north-central North America was completely covered by Lake Agassiz . Over a hundred basins, now dry or nearly so, were overflowing in

2968-582: The Great Flood of 1862 , the Santa Ana River flooded massively, and as a result "captured" several of the streams flowing into Anaheim Bay. Starved of much of its fresh water input, the bay gradually increased in salinity and the wetland area decreased. Between 1854 and 1949 the bay lost 30 percent of its area largely as a result of sedimentation and the decreased fresh water runoff available to flush it out. However, many of these streams were redirected into

3074-521: The ICS timescale, the Pleistocene is divided into four stages or ages , the Gelasian , Calabrian , Chibanian (previously the unofficial "Middle Pleistocene"), and Upper Pleistocene (unofficially the "Tarantian"). In addition to these international subdivisions, various regional subdivisions are often used. In 2009 the International Union of Geological Sciences (IUGS) confirmed a change in time period for

3180-631: The Isthmus of Panama , causing a faunal interchange between the two regions and changing ocean circulation patterns, with the onset of glaciation in the Northern Hemisphere occurring around 2.7 million years ago. During the Early Pleistocene (2.58–0.8 Ma), archaic humans of the genus Homo originated in Africa and spread throughout Afro-Eurasia . The end of the Early Pleistocene is marked by

3286-687: The La Brea Tar Pits , the Arboretum of Los Angeles , and two horse racetracks and two car racetracks ( Pomona Raceway and Irwindale Speedway ), also the RMS ; Queen Mary located in Long Beach, and the Long Beach Grand Prix , and miles of beaches—from Zuma to Cabrillo. Venice Beach is a popular attraction whose Muscle Beach used to attract throngs of tourists admiring "hardbodies". Today, it

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3392-660: The Laurentide Ice Sheet . Charles Lyell introduced the term "Pleistocene" in 1839 to describe strata in Sicily that had at least 70% of their molluscan fauna still living today. This distinguished it from the older Pliocene Epoch , which Lyell had originally thought to be the youngest fossil rock layer. He constructed the name "Pleistocene" ('most new' or 'newest') from the Greek πλεῖστος ( pleīstos ) 'most' and καινός ( kainós ( Latinized as cænus ) 'new'). This contrasts with

3498-593: The Mid-Pleistocene Transition , with the cyclicity of glacial cycles changing from 41,000-year cycles to asymmetric 100,000-year cycles, making the climate variation more extreme. The Late Pleistocene witnessed the spread of modern humans outside of Africa as well as the extinction of all other human species. Humans also spread to the Australian continent and the Americas for the first time, co-incident with

3604-892: The Pacific Ocean and encompasses mountain ranges, valleys, forests, islands, lakes, rivers, and desert. The Los Angeles River , Rio Hondo , Ballona Creek , the San Gabriel River and the Santa Clara River flow in Los Angeles County, while the primary mountain ranges are the Santa Monica Mountains and the San Gabriel Mountains . The western extent of the Mojave Desert begins in the Antelope Valley , in

3710-635: The Ruwenzori Range in east and central Africa were larger. Glaciers existed in the mountains of Ethiopia and to the west in the Atlas Mountains . In the northern hemisphere, many glaciers fused into one. The Cordilleran Ice Sheet covered the North American northwest; the east was covered by the Laurentide . The Fenno-Scandian ice sheet rested on northern Europe , including much of Great Britain;

3816-711: The Transverse Ranges of southern California, and are contained mostly within the Angeles National Forest . Most of the county's highest peaks are in the San Gabriel Mountains, including Mount San Antonio 10,068 feet (3,069 m) at the Los Angeles– San Bernardino county lines, Mount Baden-Powell 9,399 feet (2,865 m), Mount Burnham 8,997 feet (2,742 m) and Mount Wilson 5,710 feet (1,740 m). Several lower mountains are in

3922-477: The last glacial period ended about 10,000 years ago. Over 11 major glacial events have been identified, as well as many minor glacial events. A major glacial event is a general glacial excursion, termed a "glacial." Glacials are separated by "interglacials". During a glacial, the glacier experiences minor advances and retreats. The minor excursion is a "stadial"; times between stadials are "interstadials". These events are defined differently in different regions of

4028-588: The woolly rhinoceros , various giraffids , such as the Sivatherium ; ground sloths , Irish elk , cave lions , cave bears , Gomphotheres , American lions , dire wolves , and short-faced bears , began late in the Pleistocene and continued into the Holocene. Neanderthals also became extinct during this period. At the end of the last ice age, cold-blooded animals, smaller mammals like wood mice , migratory birds, and swifter animals like whitetail deer had replaced

4134-400: The 20th century, which largely confined these streams to concrete flood control channels , they frequently changed course and filled the coastal bays with varying amounts of alluvial sediment. Neither river flows into the bay at present, but sediment deposits ranging from 35 to 40 feet (11 to 12 m) thick indicate that one or both did so in the past. In its natural state, Anaheim Bay was

4240-496: The 3,133,774 households 37% had children under the age of 18 living with them, 48% were married couples living together, 15% had a female householder with no husband present, and 32% were non-families. 25% of households were one person and 7% were one person aged 65 or older. The average household size was 2.98 and the average family size was 3.61. The age distribution was 28% under the age of 18, 10% from 18 to 24, 33% from 25 to 44, 19% from 45 to 64, and 10% 65 or older. The median age

4346-534: The Anaheim–Barber City Channel shortly above the mouth. The East Garden Grove-Wintersburg Channel, longest of the three at 11.59 miles (18.65 km), empties into Bolsa Bay. Anaheim Bay is located at the mouth of Sunset Gap, one of the many breaks in the low hills and mesas that make up the Orange County coast. The gaps were formed by erosion about 40,000 years ago during the previous Ice Age , when

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4452-582: The Bolsa Chica Gun Club, which purchased the Bolsa Chica marsh from the State of California for $ 59,991. The Gun Club worked to transform the marsh lands into a duck hunting area. They constructed dikes to create freshwater ponds; the resultant change in currents caused the natural outlet of Bolsa Chica Bay to become blocked by sediment. A new channel was dug to link Bolsa Chica Bay with Anaheim Bay, transforming

4558-933: The Court of Appeal for the Second Appellate District, which is also headquartered in the Civic Center , and then to the California Supreme Court , which is headquartered in San Francisco but also hears argument in Los Angeles (again, in the Civic Center). Federal cases are appealed to the Court of Appeals for the Ninth Circuit , which hears them at its branch building in Pasadena . The court of last resort for federal cases

4664-558: The Early Pleistocene Gelasian . Early Pleistocene stages were shallow and frequent. The latest were the most intense and most widely spaced. By convention, stages are numbered from the Holocene, which is MIS1. Glacials receive an even number and interglacials receive an odd number. The first major glacial was MIS2-4 at about 85–11 ka BP. The largest glacials were 2, 6, 12, and 16. The warmest interglacials were 1, 5, 9 and 11. For matching of MIS numbers to named stages, see under

4770-409: The Earth's surface is cyclical: climate, ocean currents and other movements, wind currents, temperature, etc. The waveform response comes from the underlying cyclical motions of the planet, which eventually drag all the transients into harmony with them. The repeated glaciations of the Pleistocene were caused by the same factors. The Mid-Pleistocene Transition , approximately one million years ago, saw

4876-452: The Government of Los Angeles County. The county's voters elect a governing five-member Los Angeles County Board of Supervisors . The small size of the board means each supervisor represents over 2 million people. The board operates in a legislative, executive, and quasi-judicial capacity. As a legislative authority, it can pass ordinances for the unincorporated areas (ordinances that affect

4982-786: The Greater Los Angeles Area. LAX is operated by Los Angeles World Airports (LAWA), an agency of the City of Los Angeles. Other important commercial airports in Los Angeles County include: The following general aviation airports also are located in Los Angeles County: The U.S. Air Force operates three airports in Los Angeles County: Pleistocene The Pleistocene ( / ˈ p l aɪ s t ə ˌ s iː n , - s t oʊ -/ PLY -stə-seen, -⁠stoh- ; referred to colloquially as

5088-479: The North American west. Lake Bonneville , for example, stood where Great Salt Lake now does. In Eurasia, large lakes developed as a result of the runoff from the glaciers. Rivers were larger, had a more copious flow, and were braided . African lakes were fuller, apparently from decreased evaporation. Deserts, on the other hand, were drier and more extensive. Rainfall was lower because of the decreases in oceanic and other evaporation. It has been estimated that during

5194-434: The Pleistocene to 2.58 Ma, results in the inclusion of all the recent repeated glaciations within the Pleistocene. Radiocarbon dating is considered to be inaccurate beyond around 50,000 years ago. Marine isotope stages (MIS) derived from Oxygen isotopes are often used for giving approximate dates. Pleistocene non-marine sediments are found primarily in fluvial deposits , lakebeds, slope and loess deposits as well as in

5300-490: The Pleistocene's overall climate could be characterised as a continuous El Niño with trade winds in the south Pacific weakening or heading east, warm air rising near Peru , warm water spreading from the west Pacific and the Indian Ocean to the east Pacific, and other El Niño markers. Pleistocene climate was marked by repeated glacial cycles in which continental glaciers pushed to the 40th parallel in some places. It

5406-494: The Pleistocene, changing the start date from 1.806 to 2.588 million years BP, and accepted the base of the Gelasian as the base of the Pleistocene, namely the base of the Monte San Nicola GSSP . The start date has now been rounded down to 2.580 million years BP. The IUGS has yet to approve a type section , Global Boundary Stratotype Section and Point (GSSP), for the upper Pleistocene/Holocene boundary ( i.e.

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5512-782: The Pleistocene, the East Antarctic Ice Sheet thinned by at least 500 meters, and that thinning since the Last Glacial Maximum is less than 50 meters and probably started after ca 14 ka. During the 2.5 million years of the Pleistocene, numerous cold phases called glacials ( Quaternary ice age ), or significant advances of continental ice sheets, in Europe and North America, occurred at intervals of approximately 40,000 to 100,000 years. The long glacial periods were separated by more temperate and shorter interglacials which lasted about 10,000–15,000 years. The last cold episode of

5618-411: The Pleistocene, the plates upon which they sit probably having moved no more than 100 km (62 mi) relative to each other since the beginning of the period. In glacial periods, the sea level would drop by up to 120 m (390 ft) lower than today during peak glaciation, exposing large areas of the present continental shelf as dry land. According to Mark Lynas (through collected data),

5724-525: The appearance of Homo sapiens about 300,000 years ago. Artifacts associated with modern human behavior are unambiguously attested starting 40,000–50,000 years ago. According to mitochondrial timing techniques, modern humans migrated from Africa after the Riss glaciation in the Middle Palaeolithic during the Eemian Stage , spreading all over the ice-free world during the late Pleistocene. A 2005 study posits that humans in this migration interbred with archaic human forms already outside of Africa by

5830-400: The area. The county office also operates two magnet schools, the International Polytechnic High School and Los Angeles County High School for the Arts . There are a number of private schools in the county, most notably those operated by the Roman Catholic Archdiocese . The county's public education sector is run by numerous school districts with the Los Angeles Unified School District being

5936-409: The articles for those names. Both marine and continental faunas were essentially modern but with many more large land mammals such as Mammoths , Mastodons , Diprotodons , Smilodons , tigers , lions , Aurochs , short-faced bears , giant sloths , species within Gigantopithecus and others. Isolated landmasses such as Australia , Madagascar , New Zealand and islands in the Pacific saw

6042-415: The bay in 1964 following the construction of the Santa Ana River Mainstem Project, which channelized the part of the Santa Ana in Orange County to prevent flooding. The purpose was to reduce the total amount of water flowing into the Santa Ana, reducing its flood crests, but an unintended benefit was the restoration of the bay's natural fresh water source. In 1895, a group of Los Angeles businessmen organized

6148-550: The bay. Sheltered by a long chain of natural barrier beaches and hills, the marshes were a vast complex of ponds, streams and bogs interspersed with meadows and riparian forests. Anaheim and Bolsa Chica bays were separate bodies of water at the time with distinct ocean outlets; they were not linked until the creation of a man-made channel in 1899. The wetlands of Anaheim Bay were abundant with fish and large mammals, ranging from coyote to grizzly bears. This made it an attractive place for early Native Americans to settle. Estimates for

6254-411: The coast to the state line of Nevada . As the population increased, sections were split off to organize San Bernardino County in 1853, Kern County in 1866, and Orange County in 1889. Before the 1870s, Los Angeles County was divided into townships (many of which were amalgamations of one or more old ranchos ): As shown by the map below, Los Angeles County is bordered on the north by Kern County , on

6360-437: The county are considered ecologically significant indicators of ecosystem health and may be documented using the iNaturalist app. Los Angeles County is commonly associated with the entertainment and digital media industry; all five major film studios — Paramount Pictures , Sony Pictures , Warner Bros. , Universal Pictures , and Walt Disney Studios —are located within the county. Numerous other major industries also define

6466-532: The county is 48.7% White, 11.0% African American, 0.8% Native American, 10.0% Asian, 0.3% Pacific Islander, 23.5% from other races, and 4.9% from two or more races. 44.6% of the population are Hispanic or Latino of any race. The largest European-American ancestry groups are German (6%), Irish (5%), English (4%) and Italian (3%). 45.9% of the population reported speaking only English at home; 37.9% spoke Spanish, 2.22% Tagalog , 2.0% Chinese, 1.9% Korean , 1.87% Armenian , 0.5% Arabic , and 0.2% Hindi . The county has

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6572-409: The county's wide range of biomes it is possible to see desert bighorn sheep and green sea turtles in the same day, without crossing the county line. The range of habitats in the county is "greater than in many states, with mountains, wetlands, desert, ocean, meadows and chaparral, each with its own endemic species." There are at least 100 species of trees, and 1000 species of non-native plants, in

6678-415: The domicile of the U.S. motion picture industry since the latter's inception in the early 20th century. Los Angeles County is one of the original counties of California , created at the time of statehood in 1850. The county originally included parts of what are now Kern , San Bernardino , Riverside , Inyo , Tulare , Ventura , and Orange counties. In 1851 and 1852, Los Angeles County stretched from

6784-479: The early 21st century the bay's original outlet was re-established, restoring full tidal influence in order to benefit the local ecosystem. The San Gabriel River , which drains an extensive watershed in both Orange and Los Angeles Counties, empties into the sea less than a mile (1.6 km) to the west of Anaheim Bay. The Santa Ana River mouth is situated 11 miles (18 km) to the southeast. Several smaller streams, today mostly channelized for flood control, drain

6890-429: The east by San Bernardino County , on the southeast by Orange County , on the south by the Pacific Ocean , and on the west by Ventura County . According to the U.S. Census Bureau , the county has an area of 4,751 square miles (12,310 km ), of which 4,058 square miles (10,510 km ) (85%) is land and 693 square miles (1,790 km ) (15%) is water. Los Angeles County borders 70 miles (110 km) of coast on

6996-411: The eastern Antelope Valley – California State Parks' largest in area within the county. The California Poppy Reserve is located in the western Antelope Valley and shows off the State's flower in great quantity on its rolling hills every spring. Los Angeles International Airport (LAX), located in the Westchester district, is the primary commercial airport for commercial airlines in the county and

7102-430: The economy of Los Angeles County, including international trade supported by the Port of Los Angeles and the Port of Long Beach , music recording and production, aerospace and defense, fashion, and professional services such as law, medicine, engineering and design services, financial services. High-tech sector employment within Los Angeles County is 368,500 workers, and manufacturing employment within Los Angeles County

7208-501: The entire surface of the Earth. During interglacial times, such as at present, drowned coastlines were common, mitigated by isostatic or other emergent motion of some regions. The effects of glaciation were global. Antarctica was ice-bound throughout the Pleistocene as well as the preceding Pliocene. The Andes were covered in the south by the Patagonian ice cap. There were glaciers in New Zealand and Tasmania . The current decaying glaciers of Mount Kenya , Mount Kilimanjaro , and

7314-672: The evolution of large birds and even reptiles such as the Elephant bird , moa , Haast's eagle , Quinkana , Megalania and Meiolania . The severe climatic changes during the Ice Age had major impacts on the fauna and flora. With each advance of the ice, large areas of the continents became depopulated, and plants and animals retreating southwards in front of the advancing glacier faced tremendous stress. The most severe stress resulted from drastic climatic changes, reduced living space, and curtailed food supply. A major extinction event of large mammals ( megafauna ), which included mammoths , mastodons , saber-toothed cats , glyptodons ,

7420-444: The extinction of most large-bodied animals in these regions. The aridification and cooling trends of the preceding Neogene were continued in the Pleistocene. The climate was strongly variable depending on the glacial cycle, with the sea levels being up to 120 metres (390 ft) lower than present at peak glaciation, allowing the connection of Asia and North America via Beringia and the covering of most of northern North America by

7526-476: The first human presence at the bay range from 500 to 38,000 BC, although Hokan -speaking people are generally believed to be the earliest inhabitants, present between 6000 and 3500 BC. As one of the few safe natural anchorages along the Southern California coast, Anaheim Bay has been an important strategic position in Orange County since at least the mid-1800s. During the Mexican–American War , Commodore Robert F. Stockton repulsed an attempted landing by

7632-414: The glacial range, which have their own glacial history depending on latitude, terrain and climate. There is a general correspondence between glacials in different regions. Investigators often interchange the names if the glacial geology of a region is in the process of being defined. However, it is generally incorrect to apply the name of a glacial in one region to another. For most of the 20th century, only

7738-450: The historical terminology was established. Corresponding to the terms glacial and interglacial, the terms pluvial and interpluvial are in use (Latin: pluvia , rain). A pluvial is a warmer period of increased rainfall; an interpluvial is of decreased rainfall. Formerly a pluvial was thought to correspond to a glacial in regions not iced, and in some cases it does. Rainfall is cyclical also. Pluvials and interpluvials are widespread. There

7844-445: The immediately preceding Pliocene ("newer", from πλείων ( pleíōn , "more") and kainós ) and the immediately subsequent Holocene ("wholly new" or "entirely new", from ὅλος ( hólos , "whole") and kainós ) epoch , which extends to the present time. The Pleistocene has been dated from 2.580 million (±0.005) to 11,700 years BP with the end date expressed in radiocarbon years as 10,000 carbon-14 years BP. It covers most of

7950-613: The large amounts of material moved about by glaciers. Less common are cave deposits, travertines and volcanic deposits (lavas, ashes). Pleistocene marine deposits are found primarily in shallow marine basins mostly (but with important exceptions) in areas within a few tens of kilometres of the modern shoreline. In a few geologically active areas such as the Southern California coast, Pleistocene marine deposits may be found at elevations of several hundred metres. The modern continents were essentially at their present positions during

8056-545: The largest Native American population of any county in the nation: according to the 2000 census, it has more than 153,550 people of indigenous descent, and most are from Latin America . As estimated by the Public Policy Institute of California in 2008, Los Angeles County is home to more than one-third of California's undocumented immigrants , who make up more than ten percent of the population. Los Angeles County

8162-724: The largest one running public schools primarily within the city of Los Angeles and its immediately neighboring cities. The county's most visited park is Griffith Park , owned by the city of Los Angeles. The county is also known for the annual Rose Parade in Pasadena, the annual Los Angeles County Fair in Pomona, the Los Angeles County Museum of Art , the Los Angeles Zoo , the Natural History Museum of Los Angeles County ,

8268-543: The largest remaining coastal wetlands in California between Monterey Bay and the mouth of the Tijuana River , with 1,449 acres (586 ha) of salt flats, lagoons and tidal streams. A set of floodgates regulates the water level between Bolsa Bay and Huntington Harbor. While Bolsa Bay was once a separate body of water, its ocean outlet silted up in the early 1900s after a man-made channel was cut to link it to Anaheim Bay. In

8374-606: The last census of 583,364 people (i.e., 1,152,564 births minus 569,200 deaths) and a decrease due to net migration of 361,895 people. Immigration resulted in a net increase of 293,433 people, and migration from within the United States resulted in a net decrease of 655,328 people. The racial makeup of Los Angeles County was 4,936,599 (50%) White, 1,346,865 (13.7%) Asian, 856,874 (9%) African American, 72,828 (0.7%) Native American, 26,094 (0.3%) Pacific Islander, 2,140,632 (21.8%) from other races, and 438,713 (4.5%) from two or more races. Non-Hispanic whites numbered 2,728,321, or 28% of

8480-526: The latest period of repeated glaciation , up to and including the Younger Dryas cold spell. The end of the Younger Dryas has been dated to about 9700 BCE (11,700 calendar years BP). The end of the Younger Dryas is the official start of the current Holocene Epoch . Although it is considered an epoch, the Holocene is not significantly different from previous interglacial intervals within the Pleistocene. In

8586-466: The lower Palaeolithic they disappeared, and the only hominin species found in fossilic records is Homo erectus for much of the Pleistocene. Acheulean lithics appear along with Homo erectus , some 1.8 million years ago, replacing the more primitive Oldowan industry used by A. garhi and by the earliest species of Homo . The Middle Paleolithic saw more varied speciation within Homo , including

8692-434: The majority of which are Catholic. Roman Catholic adherents number close to 40% of the population. There were 202 Jewish synagogues , 145 Buddhist temples, 38 Muslim mosques , 44 Baháʼí Faith worship centers, 37 Hindu temples , 28 Tenrikyo churches and fellowships, 16 Shinto worship centers, and 14 Sikh gurdwaras in the county. The Roman Catholic Archdiocese of Los Angeles has approximately 5 million members and

8798-478: The megafauna and migrated north. Late Pleistocene bighorn sheep were more slender and had longer legs than their descendants today. Scientists believe that the change in predator fauna after the late Pleistocene extinctions resulted in a change of body shape as the species adapted for increased power rather than speed. The extinctions hardly affected Africa but were especially severe in North America where native horses and camels were wiped out. In July 2018,

8904-508: The mountain, canyon, and desert areas one may find Vasquez Rocks Natural Area Park , where many old Westerns were filmed. Mount Wilson Observatory in the San Gabriel Mountains is open for the public to view astronomical stars from its telescope, now computer-assisted. Many county residents find relaxation in water skiing and swimming at Castaic Lake Recreation Area – the county's largest park by area – as well as enjoying natural surroundings and starry nights at Saddleback Butte State Park in

9010-437: The north and north-east sides of the bay, respectively. The bay is divided into an outer and inner deep water harbor. The triangular, 94-acre (38 ha) outer harbor is man-made, protected by two converging rubble breakwaters and maintained to a depth of 43 feet (13 m). The west breakwater has a length of 3,500 feet (1,100 m) and the east breakwater is 3,950 feet (1,200 m). The 96 acres (39 ha) inner harbor

9116-559: The northeastern part of the county. Most of the population of Los Angeles County resides in the south and southwest, with major population centers in the Los Angeles Basin , San Fernando Valley , and San Gabriel Valley . Other population centers are found in the Santa Clarita Valley , Pomona Valley , Crescenta Valley and Antelope Valley . The county is divided west-to-east by the San Gabriel Mountains , which are part of

9222-643: The northern, western, and southwestern parts of the county, including the San Emigdio Mountains , the southernmost part of Tehachapi Mountains and the Sierra Pelona Mountains . Los Angeles County includes San Clemente Island and Santa Catalina Island , which are part of the Channel Islands archipelago off the Pacific Coast . The Northern part of the county has a Desert climate , while

9328-487: The only significant natural island in the bay complex. The larger NASA Island was created for rocket testing in the mid-1960s. The islands now provide 65 acres (26 ha) of upland habitat, or the only permanently dry land within the refuge. Being located within the naval base, public access to the wildlife refuge is highly restricted. Connected to the southeast end of Huntington Harbor is Bolsa Bay, which has retained many of its original wetlands. The Bolsa Chica wetlands are

9434-522: The outlet for a vast expanse of estuarine salt marshes that stretched across what is now southeastern Los Angeles County and western Orange County. The Anaheim Bay marshes covered more than 5,000 acres (2,000 ha) and the Bolsa Chica marshes covered a further 2,300 acres (930 ha), although the extent of these wetlands was likely much greater and varied with the seasonal flooding on the San Gabriel and Santa Ana rivers and smaller streams that flowed into

9540-472: The period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology . The name is a combination of Ancient Greek πλεῖστος ( pleîstos ) 'most' and καινός ( kainós ; Latinized as cænus ) 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by

9646-617: The population. Hispanic or Latino residents of any race numbered 4,687,889 (48%); 36% of Los Angeles County's population was of Mexican ancestry, 3.7% Salvadoran, and 2.2% Guatemalan heritage. The county has a large population of Asian Americans , being home to the largest numbers of Burmese , Cambodian , Chinese , Filipino , Indonesian , Korean , Sri Lankan , Taiwanese , and Thai outside their respective countries. The largest Asian groups in Los Angeles County are 4.0% Chinese, 3.3% Filipino, 2.2% Korean, 1.0% Japanese, 0.9% Vietnamese, 0.8% Indian, and 0.3% Cambodian. The racial makeup of

9752-417: The ratio of O to O (two isotopes of oxygen ) by mass (measured by a mass spectrometer ) present in the calcite of oceanic core samples is used as a diagnostic of ancient ocean temperature change and therefore of climate change. Cold oceans are richer in O , which is included in the tests of the microorganisms ( foraminifera ) contributing the calcite. A more recent version of

9858-455: The recent period of repeated glaciations. The name Plio-Pleistocene has, in the past, been used to mean the last ice age. Formerly, the boundary between the two epochs was drawn at the time when the foraminiferal species Hyalinea baltica first appeared in the marine section at La Castella, Calabria, Italy. However, the revised definition of the Quaternary , by pushing back the start date of

9964-420: The rest of the county generally is a mix of Semi-arid and a hot-summer Mediterranean climate . There is rainfall mostly in the wintertime, but the mountains in the north-central part of the county have snow during winter. In 2019, the median household income in the county was $ 72,797. Los Angeles County had a population of 9,818,605 in the 2010 United States Census . This includes a natural increase since

10070-407: The sampling process makes use of modern glacial ice cores. Although less rich in O than seawater, the snow that fell on the glacier year by year nevertheless contained O and O in a ratio that depended on the mean annual temperature. Temperature and climate change are cyclical when plotted on a graph of temperature versus time. Temperature coordinates are given in the form of

10176-527: The sea level was lower and rivers entrenched valleys into the coastal plain. When sea levels rose following the glacial melt at the end of the Pleistocene , the valleys or gaps were backfilled by sea water and became bays. The area is located within the historic floodplain of the San Gabriel and Santa Ana Rivers , whose mouths are located to the north and south of the bay, respectively. Before urbanization in

10282-632: The sole factor responsible for the variations in climate since they explain neither the long-term cooling trend over the Plio-Pleistocene nor the millennial variations in the Greenland Ice Cores known as Dansgaard-Oeschger events and Heinrich events. Milankovitch pacing seems to best explain glaciation events with periodicity of 100,000, 40,000, and 20,000 years. Such a pattern seems to fit the information on climate change found in oxygen isotope cores. In oxygen isotope ratio analysis, variations in

10388-423: The state Legislature to authorize the transfer of all courthouses to the state government in 2008 and 2009 (so that judges would have direct control over their own courthouses). Courthouse security is still provided by the county government under a contract with the state. Unlike the largest city in the United States, New York City , all of the city of Los Angeles and most of its important suburbs are located within

10494-421: The study of cyclical climate changes. The glacials in the following tables show historical usages, are a simplification of a much more complex cycle of variation in climate and terrain, and are generally no longer used. These names have been abandoned in favour of numeric data because many of the correlations were found to be either inexact or incorrect and more than four major glacials have been recognised since

10600-447: The two bays into one continuous body of water. A dam was then built across the channel to raise the fresh water level in Bolsa Chica and prevent salt water intrusion from Anaheim Bay. The entrance of the bay was widened by the U.S. Navy in 1944 and breakwaters constructed in order to serve Naval Air Station Los Alamitos . In 1990 a $ 150 million proposal by the Navy was proposed to add

10706-622: The upper boundary). The proposed section is the North Greenland Ice Core Project ice core 75° 06' N 42° 18' W. The lower boundary of the Pleistocene Series is formally defined magnetostratigraphically as the base of the Matuyama (C2r) chronozone , isotopic stage 103. Above this point there are notable extinctions of the calcareous nannofossils : Discoaster pentaradiatus and Discoaster surculus . The Pleistocene covers

10812-1022: The urban areas of the county. Charismatic biodiversity indicator species native to the area include three species of amphibian ( Baja California chorus frog , black-bellied slender salamander , western toad ), 14 species of bird ( acorn woodpecker , California quail , canyon wren , cinnamon teal , great blue heron , great horned owl , greater roadrunner , hooded merganser , Northern harrier , red-tailed hawk , red-winged blackbird , spotted towhee , western bluebird , western meadowlark ), nine kinds of invertebrates ( Behr's metalmark , bramble green hairstreak , bumblebees , El Segundo blue butterfly , harvester ants , Lorquin's admiral , North American Jerusalem crickets , Sara orangetip , velvet ants ), five mammals ( bobcat , dusky footed woodrat , gray fox , mountain lion , mule deer ), and six reptiles ( California kingsnake , coachwhip snake , gopher snake , side-blotched lizard , western pond turtle , western rattlesnake ). Any observations of these species within

10918-506: The whole county, like posting of restaurant ratings, must be ratified by the individual city). As an executive body, it can tell the county departments what to do, and how to do it. As a quasi-judicial body, the Board is the final venue of appeal in the local planning process, and holds public hearings on various agenda items. As of 2020, the Board of Supervisors oversees a $ 35.5 billion annual budget and over 112,000 employees. The county government

11024-463: Was 32 years. For every 100 females, there were 97.7 males. For every 100 females age 18 and over, there were 95.0 males. The median personal earnings for all workers 16 and older in Los Angeles County are $ 30,654, slightly below the US median; earnings, however vary widely by neighborhood, race and ethnicity, and gender. The median household income was $ 42,189 and the median family income was $ 46,452. Males had

11130-543: Was a series of glacials and interglacials, stadials and interstadials, mirroring periodic climate changes. The main factor at work in climate cycling is now believed to be Milankovitch cycles . These are periodic variations in regional and planetary solar radiation reaching the Earth caused by several repeating changes in the Earth's motion. The effects of Milankovitch cycles were enhanced by various positive feedbacks related to increases in atmospheric carbon dioxide concentrations and Earth's albedo. Milankovitch cycles cannot be

11236-550: Was almost evenly split over Proposition 8 , which amended the California Constitution to ban same-sex marriages. The county voted for the amendment 50.04% with a margin of 2,385 votes. The Los Angeles County Superior Court is the county's court of general jurisdiction, while the U.S. District Court for the Central District of California may hear cases where federal jurisdiction is present. Both are headquartered in

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