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83-549: Mount San Antonio's sometimes snow-capped peaks are visible on clear days and dominate the view of the Los Angeles Basin skyline . The peak and a subsidiary one to the west form a double summit of a steep-sided east–west ridge . The summit is accessible via a number of connecting ridges along hiking trails from the north, east, south, and southwest. The Tongva call the mountain Yoát or Joat , which means snow , and

166-460: A 8-mile (13 km) course over roads and trails ends at the main peak for an approximately 4,000-foot (1,200 m) elevation gain. Hunting is allowed, but is regulated and requires a license. The first development in the area came in the Civil War era, and was focused on exploitation of the area's resources both by independent homesteaders and for use by the populated lowland areas. Some of

249-606: A broad anticline that is truncated by the Santa Monica fault zone. The central block contains both marine and non-marine clastic rock units interbedded with volcanic rocks that are late Cretaceous to Pliocene in age. Pliocene and Quaternary strata are most visible within the central block. Structurally, there is a synclinal trough. The northeastern block contains fine to coarse grained clastic marine rocks of Cenozoic age. Locally, middle Miocene volcanics can be seen as well as Eocene to Miocene aged non-marine sedimentary rocks. There

332-525: A general timeline to categorize the sequence of depositional events in the LA Basin's evolution and they are as follows: During pre- Turonian , metamorphosed sedimentary and volcanic rocks are present that serve as the two major basement rock units for the LA Basin. Large-scale movement along the Newport–Inglewood zone juxtaposed the two bedrock units along the east and west margins. During this phase,

415-452: A higher probability of experiencing seismic activity. The region experiences earthquakes that are mostly mild (magnitude ≤2.25). However moderate earthquakes (magnitude 4.9 to 6.4) have been reported. Earthquakes of moderate magnitude are very infrequent. This fault zone is the most notable feature within the basin that is a single strand with local (fault) splays. The fault zone is also marked by low hills, scarps, and ten anticlinal folds in

498-524: A loop corresponding to the present-day Mt. Baldy Trail and Devil's Backbone Trail. Rental cabins were also built in Evey Canyon. Access to the upper canyon was impeded by the precarious nature of the trail going over the Hog Back slide, but by the turn of the century Dell's Camp nevertheless entertained as many as a hundred guests in a weekend. Charles Baynham built a second camp nearby in 1907, and in

581-472: A major unconformity at the base of the middle Miocene units. Emergence did not occur at the same rate or in all sections of the basin. During this time, the basin was covered by a marine embayment. Rivers sourced in the highlands brought large amounts of detritus to the northeastern edge of the basin. During this period, the Topanga formation was also being deposited. The present form and structural relief of

664-570: A mile-long pipeline, remnants of which can still be seen, running all the way from San Antonio Creek. The remains of the Gold Ridge Diggings (a.k.a. Agamemnon mine) (1897-ca. 1904) are found near the headwaters of San Antonio Canyon, in the canyon below the Ski Hut. The miners were kept supplied by sheep hunter turned merchant Fred Dell, who built Dell's Camp near the present Mt. Baldy Village, and by mule driver Fletcher Manker, who built

747-500: A number of experiments involving bouncing a beam of light off a reflector at Lookout Mountain , a prominence 3.2 miles (5.1 km) southwest of the peak, from the observatory at Mount Wilson some 22 miles (35 km) away. During Prohibition , the area became known as a place where one could get a drink away from the watchful eyes of the police. Former Yosemite concessionaire Foster Curry, his wife Ruth Curry, and Ruth's second husband, movie star Edmund Burns , turned Camp Baldy into

830-555: A number of summer routes to the summit involving cross-country travel or scrambling, and it is possible to rappel down the canyon of San Antonio Creek. The ski hut is operated by the Sierra Club Angeles Chapter and available for year-round use on weekends. It marks the approximate halfway point on the Ski Hut Trail, at an elevation of 8,200 ft. It has a fully-equipped kitchen, piped water, solar lighting,

913-539: A playground for affluent residents of Los Angeles, with a swimming pool, casino, and a dance pavilion. In 1935–1936 the Civilian Conservation Corps built a wide trail along the Devil's Backbone from Mt. Baldy Notch to the summit, a route which had previously been narrow and dangerous due to the precipitous drops on one, or in some areas both, sides. Aurelia Harwood , the first female president of

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996-545: A right-stepping en echelon pattern. It is located in the southwest portion of the basin and is a strike-slip margin. There are several oil fields that run parallel to this fault. This fault lies on the eastern border of the basin and mergers with the Elsinore Fault in the canyon of the Santa Ana River, one of the upper branches of the fault. This fault is a reverse right-oblique fault. It is most known for

1079-614: A series of bitter conflicts between the San Antonio Water Company and the camp owners. Pollution of the watershed and an 1899 brush fire led the company to buy Dell's Camp and close it, wrest legal control of the road away from Baynham, close off the canyon with locked gates, and station armed guards to keep out intruders. But after some time and various legal battles, the company decided to profit from recreation rather than discouraging it. It bought Baynham's Camp in 1907 but then hired Baynham to manage it, charging tolls on

1162-545: A shallow marine environment. Tectonic instability coupled with volcanic activity in rapidly subsiding areas during the Middle Miocene set the stage for the modern basin. The basin formed in a submarine environment and was later brought back above sea level when the rate of subsidence slowed. There is much discussion in the literature about the geologic time boundaries when each basin forming event took place. While exact ages may not be clear, Yerkes et al. (1965) provided

1245-502: A store at what is now known as Manker Flat. Gold mining began in Icehouse Canyon in 1892. The Hocumac and Gold Ridge mines were unsuccessful due to the uncertain water supply, the low amount of gold in the ore, and a water-pollution lawsuit filed by downslope farmers. The late 19th century saw increased interest in the area for its own qualities and for recreation rather than for its resources. In 1875 an army surveying party made

1328-650: A white belly and a big, bushy tail) from the California ground squirrel , which is spotted and has a gray area on the back of its neck. Hiking trails reach the summit from four sides of the mountain, and one can access the Devil's Backbone trail by skipping the Mt. Baldy Notch trail with taking chair #1 at Mount Baldy Resorts during any season. The trails vary in difficulty, and there are plenty of options for novices as well as experienced hikers. Mt. Baldy Notch – (3.5 miles one way): The trail begins at Manker Flats, where

1411-468: A wood-burning stove, dormitory loft beds for about sixteen visitors, and an outhouse with a view. The hut is located at the base of Baldy Bowl , recognized as a superb skiing area in the early 1930s. The Ski Mountaineers section of the Sierra Club, formed in 1935, was granted permission by the U.S. Forest Service to construct a hut in this location. The hut was built by volunteers, who carried all of

1494-607: Is 9,996 feet (3,047 m). The mountain's southern watershed drains into San Antonio Creek , the north side into Lytle Creek and the Fish Fork of the San Gabriel River . San Antonio and Lytle Creeks are part of the Santa Ana River watershed. San Antonio Creek descends through a deep canyon which has several waterfalls, the last about 75 feet (23 m) high. East of the summit is Mount Harwood , which

1577-638: Is a basal marine conglomeratic sandstone, followed by a dominantly basaltic middle layer of multiple submarine lava flows and tuffs. The youngest part of this unit is a sedimentary breccia, conglomerate, sandstone, and a siltstone . The earliest deposits of the Topanga Group appear to reflect the continuation of a shift in shoreline that can be seen in both the Sespe and Vaqueros formations. Eruptions from one or more of volcanic centers locally and temporarily interrupted sedimentation. The Puente Formation

1660-585: Is a deep-marine formation that is characterized by pro-delta sediments and an overlapping fan system. This unit lies above the Topanga Group giving it a Late Miocene depositional age and is divided into four members. The La Vida Member is a micaceous, platy siltstone with subordinate amounts of thin-bedded feldspathic sandstone. The next member is the Soquel, which is a thick bedded to massive micaceous sandstone. Locally abundant siltstone, conglomerate, and intraformational breccia can also be seen in this member. Above

1743-412: Is a higher ratio of chinquapin to manzanita. Other shrubs on the mountain include mountain whitethorn , buckwheat , and mountain gooseberry . Wildflower species include Galium parishii, San Gabriel alumroot , gray monardella , pumice alpinegold , Parry's pussypaws , Nuttall's sandwort , and caulanthus . There are also Ross's sedge and rockcress . Oreonana vestita, a type of mountainparsley,

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1826-591: Is a large decline from the almost 1 billion barrels per year produced in the late 1970s. Oil fields include: San Antonio Creek (San Bernardino County) San Antonio Creek is a major stream in Los Angeles County and San Bernardino County , California , draining southwards from Mount San Antonio in the San Gabriel Mountains into Chino Creek , a tributary of the Santa Ana River . Upon leaving San Antonio Canyon and entering

1909-522: Is a largely unconsolidated unit and is composed mostly of gravel and floodplain sediments. The sediments that mark the top of the basin can be found in modern streams/rivers and at the base of the foothills. The history of this basin begins with the subduction of Pacific plate underneath the North American plate in the beginning of the Mesozoic. During this subduction event, two smaller plates,

1992-444: Is a mid-Miocene fault block that revealed a northwest trending ridge of Paleocene age rocks. This structural feature is important because it revealed many oil traps and orientation of the beds indicate the age of subsidence in this portion of the basin. This particular anticline is the most notable subsurface feature within the basin. Deformation events such as erosion of the uplifted crustal blocks, initiation of various faults, and

2075-700: Is a sedimentary basin located in Southern California , in a region known as the Peninsular Ranges . The basin is also connected to an anomalous group of east–west trending chains of mountains collectively known as the Transverse Ranges . The present basin is a coastal lowland area, whose floor is marked by elongate low ridges and groups of hills that is located on the edge of the Pacific plate . The Los Angeles Basin, along with

2158-654: Is adapted to talus. Desert bighorn sheep ( Ovis canadensis nelsoni ) are found in the area, mostly above 7000', and they lamb in the area. Their population is less threatened than those of other subspecies in California. Unlike animals of this subspecies in the Mojave Desert , those in the San Gabriel Mountains cannot be legally hunted and need not compete with aggressive feral burros for food or water. Grizzly bears ( Ursus arctos ), featured on

2241-419: Is also an anticline in the northeastern block. Homogeneous evolution of this basin did not occur due to dynamic tectonic activity. Despite the active setting, there are over 9,100 m of strata within the basin. The dynamic setting was also responsible for the heterogeneous deposition of each formation. It is common for rock units of the same depositional event to have different names in different locations within

2324-568: Is in turn connected by a narrow ridge, "The Devil's Backbone," to a pass known as the Baldy Notch. At the Notch there is a ski resort , the closest one to Los Angeles. South of the resort, and connected to its ski lift by an asphalt road, lies Mt Baldy Village . There are no roads or maintained trails connecting the mountain to the less populated region to its north, but a use trail leads over Dawson Peak and Pine Mountain to Wright Mountain and

2407-401: Is marked by two sandstone, siltstone and shale units. There are also characteristic mollusk fossils that indicate the area was dominately shallow marine. The Topanga Group is the next major formation in the stratigraphic sequence and infills the topography on older rocks. It is a mixed sedimentary and volcanic unit whose base is an erosional unconformity. The unit consists of 3 parts: First

2490-408: Is now known as Icehouse Canyon. Because the canyon is deep, its north-facing slope retains snow late into the spring, and in 1859 Victor Beaudry and Damien Marchessault built an icehouse there. The ice was brought down from the mountains to Los Angeles by mule and wagon and sold door to door, as well as being used at Beaudry and Marchessault's ice cream saloon, the only one in the city. ( Marchesseault

2573-417: Is remarkable due to the relatively small size and youth of the basin. The basin currently has about 40 active oil fields that collectively have 4,000 operating wells. In 1904, there were over 1,150 wells in the city of Los Angeles alone. Tight spacing and continued pumping of the wells resulted in most of the wells to dry up. Most recent data indicates that 255 million barrels of oil were produced in 2013. This

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2656-521: Is split into two sub-facies known as the Pico and Repetto Members . These members represent a distinct change in the depositional environment and are of Pleistocene age. The Repetto is the older of the two members and is composed of interbedded fine to coarse grained siltstone, mudstone, and sandstone. The Pico Member is mostly made of massive siltstones and sandstones interbedded with minor silty-sandstones. Holocene alluvium and Quaternary sediments

2739-468: Is the Whittier and Newport–Inglewood faults that have dictated the seismic behavior within the basin. The Los Angeles basin is still active tectonically and the region continues to experience earthquakes as a result. Due to the number of faults and fault splays, seismic activity is not concentrated in one particular area. The cities that are overlain by the Newport–Inglewood and Whittier fault zones have

2822-523: Is the first to appear above the great unconformity and is marked by interbedded mudstones, sandstones and pebbly sandstones. This bed sequence indicates an alluvial fan, meandering stream or braided stream origin. Upward from the Sespe Formation toward the Vaqueros , the grains become finer and the beds become thinner; indicating a transition to a shallow marine environment. The Vaqueros Formation

2905-469: Is used to correlate strata throughout the basin. The record of the Cenozoic activity begins above this unconformity. The stratigraphic record for this basin indicates that it began as a non-marine environment and then transgressed to a deep ocean system. The oldest basement units of this basin are of both sedimentary and igneous origin. The sedimentary unit was metamorphosed as a result of slippage of

2988-462: The Mohave call it Avii Kwatiinyam . The name Mount San Antonio was probably bestowed by Antonio Maria Lugo , owner of a rancho near present-day Compton circa 1840, in honor of his patron saint, Anthony of Padua . The mountain is almost always referred to as "Mount Baldy" by locals, to the point where many may not recognize the name "Mount San Antonio." When American settlers arrived and surveyed

3071-652: The Newport–Inglewood fault and is known as the Catalina Schist . The Catalina Schist can be found on the southwestern edge of the basin and is predominantly a chlorite-quartz schist. Closer to the Newport–Inglewood fault zone, garnet -bearing schists and metagabbros occur. The Santa Monica Slate can be observed in the northwestern block of the basin. The eastern complex is characterized by Santiago Peak Volcanics. This rock unit contains andesitic breccias , flow, agglomerates and tuffs . The Sespe Formation

3154-529: The Pacific Crest Trail , overlooking the town of Wrightwood . A weather station located around 7,700 feet was run during the 1960s; it recorded an average of 131 inches of snow per year. Snow peaks late in the season; in April 1967, 120 inches of snow fell. Mount San Antonio lies in the front range of the San Gabriel Mountains , one of the Transverse Ranges of Southern California, formed around

3237-572: The Pomona Valley , including Claremont , Montclair , and Chino . The creek joins Chino Creek in northwestern Chino, 9 miles (14 km) upstream from the larger stream's mouth at the Santa Ana River. The creek's upper canyon was the site of some of the heaviest gold mining activity in the San Gabriels during the mid-19th century. When the gold deposits petered out, the streambanks played host to various mountain resort camps beginning in

3320-563: The San Andreas Fault system. The Transverse Ranges were formed because of a dog-leg bend in the San Andreas, which is a transform fault . The bend makes it difficult for the two plates to move smoothly past one another, and mountains were raised as a result. The prehistoric Hog Back landslide lies in the canyon of San Antonio Creek at 4000' elevation. When the slide occurred, it dammed the river, whose depth built up until

3403-756: The Santa Barbara Channel , the Ventura Basin , the San Fernando Valley , and the San Gabriel Basin , lies within the greater Southern California region. The majority of the jurisdictional land area of the city of Los Angeles physically lies within this basin. On the north, northeast, and east, the lowland basin is bound by the Santa Monica Mountains and Puente, Elysian, and Repetto hills. To

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3486-517: The Sierra Club , was active in the area. Mount Harwood , a subsidiary peak of Mount Baldy, is named for her. The Sierra Club built a lodge, also named after her, at Manker Flats in 1930. It is open to Sierra Club members. In 1935 the club added a mountain hut, known as the "ski hut," by the base of the Baldy Bowl near the headwaters of San Antonio Creek. The ski hut burned down that year but

3569-635: The Baldy Notch Service Road can be taken to the notch. The trail provides scenic views at the notch, and other trails ahead. Devil's Backbone – (3.2 miles one way from Notch: A service road at Mt. Baldy Notch leads to the Devil's Backbone trailhead and continues to the main peak. Mt. Baldy Trail – (6.5 miles one way to Mt. Baldy Summit): This is the oldest and longest trail to the summit. Because it starts at Mt. Baldy Village, it has almost 6000' of elevation gain. Icehouse Canyon – (3.7 miles one way): The Icehouse Canyon trail begins in

3652-459: The Holocene is characterized by non marine gravel, sand and silt. This phase also includes the late-stage compressional deformation responsible for the formation of the hydrocarbon traps. Four major faults are present in the region and divide the basin in the central, northwest, southwest, and northeast structural blocks. These blocks not only denote their geographic location, but they indicate

3735-591: The Monterey and Juan de Fuca plates, also began to subduct underneath the North American plate. Around 20Ma, the Monterey plate attached to and followed the motion of the Pacific plate. Later, subduction of the Pacific-Monterey ceased and the plate margin was converted to a transform boundary. The North America/Pacific-Monterey transform boundary began to move north and created crustal extension. This rifting

3818-506: The San Gabriels are believed to be descended from this group. Black bears are relatively shy and are almost never known to harm humans. Rabbits and coyotes are found near San Antonio Creek at low elevations, typically below 2000'. The most common species of rabbits are the black-tailed jackrabbit ( Lepus californicus ) and the desert cottontail ( Sylvilagus audubonii ), the jackrabbit being distinguished by its huge ears. Western gray squirrels live in oak forests at low elevations, on both

3901-809: The Soquel lies the Yorba Member. This member is a sandy siltstone that is interbedded with a fine-grained sandstone. The Sycamore Canyon Member contains lenses of conglomerate, conglomeratic sandstone, and sandstone. Sandy siltstone and fine-grained sandstones are interbedded with the aforementioned rock types. The Monterey Formation is characterized by abnormally high silica content compared to most clastic rocks. There are also silica-cemented rocks known as porcelanite and porcelanite shale . While this formation has distinguishable beds, there are many shale, sandstone, and mudstone beds that have normal amounts of silica. This sequence of this formation indicates an off-shore marine environment. The Fernando Formation

3984-487: The Whittier, Brea-Olinda, Sansinena, oil fields. There is an anticline that runs parallel to the Whittier fault that is evidence for compressional deformation during the late Miocene to early Pliocene. Thinning and pinch-out of the Pliocene sandstones are evidence for uplift during this same time period. The Anaheim nose is a subsurface feature that was discovered by geophysical surveys and exploratory drilling in 1930. It

4067-522: The basin lies on the boundary of the Transverse and Peninsular Ranges, this basin experiences both compressional and strike slip tectonics. During the early Pliocene, also identified as the "Basin Disruption" phase, deformation and folding occurred as a result of fault movement and a slight rotation event. While movement along the San Andreas Fault is responsible for the placement of the basin, it

4150-402: The basin was above sea level. The hallmarks of this phase were successive shoreline transgression and regression cycles. Deposition of older marine and non-marine sediments began to fill the basin. Towards the end of this phase, the shoreline began to retreat and deposition continued. After the deposition of the pre-Turonian units, there was a large emergence and erosion that can be observed as

4233-471: The basin was largely established during this phase of accelerated subsidence and deposition which occurred during the late Miocene and continued through the early Pleistocene. Clastic sedimentary rocks from the highland areas (to the north and east) moved down the submarine slopes and infilled the basin floor. Subsidence and sedimentation most likely began in the southern portion basin. Subsidence and Deposition occurred simultaneously, without interruption, until

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4316-587: The basin's evolution, which began in the Upper Cretaceous and ended in the Pleistocene . This basin can be classified as an irregular pull-apart basin accompanied by rotational tectonics during the post- early Miocene . Before the formation of the basin, the area that encompasses the Los Angeles basin began above ground. A rapid transgression and regression of the shoreline moved the area to

4399-401: The basin. The thickness of these oil sands range from hundreds to thousands of feet. Anticlines and faulted anticlines are the structural features that are also responsible for trapping oil. The first reported oil-producing well was discovered in 1892 on the land that is presently beneath Dodger Stadium . This basin was responsible for half of the states oil production until the (90's?). This

4482-478: The basin. This may be a result of large variation in clast size as with the upper Pliocene Pico Formation in the northwestern part of the basin and the Upper Fernando Formation in the southwest part of the basin. The Los Angeles Basin contains what is known as the " Great Unconformity " which has been interpreted as a large-scale erosional event in the basement rock unit. This unconformity

4565-565: The broad alluvial plain of the Pomona Valley , it is known as the San Antonio Wash or the San Antonio Creek Channel , the former referring to the creek's seasonal dry nature below the mouth of San Antonio Canyon . The creek is 20.7 miles (33.3 km) long and has a drainage basin of about 37 square miles (96 km ). San Antonio Creek rises on the southeast flank of Mount San Antonio (Mount Baldy) ,

4648-466: The building materials up on their backs; it was completed in January 1936. The original hut burned to the ground on September 20, 1936, but was rebuilt, using burros to transport the building supplies, with the replacement hut completed that winter. The rebuilt hut is preserved as much as possible in its original condition, except that the women’s dormitory has been converted to a tool and storage room, and

4731-537: The climb through Mt. Baldy Village to the base of the ski lifts is popular. It has been used as the finish of the penultimate stage of the 2011 , 2012 , 2015 and 2019 Amgen Tour of California . It was also featured in the 2017 Tour of California as the fifth stage of the race. Since 1965, each Labor Day, the San Antonio Canyon Town Hall has sponsored a "Run to the Top" on Mt. Baldy in which

4814-440: The damage done by the 1969 flood. Hydroelectric plants along San Antonio Creek are tied to the electric grid. The lower land area of the mountain consists of an ecological community known as yellow pine forest. Tree species include lodgepole pine , Jeffrey pine (also known as western yellow pine), white fir , and some sugar pine . These forests are fairly sparse, and are intermixed with chaparral and oak savannah. Higher up,

4897-571: The development of the submarine channel led to the anticline's formation. Fold initiation began in the late-Miocene to early Pliocene period of deformation. There are many other anticlines within the basin and isopach data suggests that the formation of these folds occurred mostly during the Pliocene. The La Brea Tar Pits are pools of stagnant asphaltum that have been found on the basin's surface. These "pools" are important because hundreds of thousands of late Pleistocene bones and plants have been found. These pits allowed scientists to better understand

4980-433: The early 20th century. Also around this time, canals were built from the mouth of San Antonio Canyon to irrigate farms in the creek's wide floodplain . The Los Angeles Flood of 1938 destroyed much of the early development along the creek. The San Antonio Dam was built between 1952 and 1956 by the U.S. Army Corps of Engineers to provide flood control. In recent years, the lower watershed has become much more urbanized, and

5063-408: The ecosystem at that particular point in the geologic past. Accumulations of oil and gas occur almost wholly within strata of the younger sequence and in areas that are within or adjacent to the coastal belt. The Puente formation has proved to be the most notable reservoir for petroleum in the basin. The primary reason for the high abundance of oil is because the oil sands are well saturated within

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5146-551: The failing roof panels had to be replaced, again transported to the hut by human power. Manker Flats Campground is available for the public to camp in on a first come-first served mechanism. It is located 3 miles northeast of Mt. Baldy Village on Mt. Baldy road, in an open pine forest. It boasts 21 campsites with features such as stoves, piped water, toilets and tables. However, there are no facilities for showers or sanitary disposal. Fees for camping overnight are $ 12 per night, and an additional $ 5 for extra vehicles. For road cyclists,

5229-664: The first people to live permanently in the area were Mormon settlers in Lytle Creek Canyon (1851), orange farmer Madison Kincaid (1865) and fruit farmer and beekeeper A.A. Dexter (ca. 1875). A sawmill was built in 1870 upstream from today's Mt. Baldy Village, but it either burned down or was destroyed in the flood of 1884. Ever since 1882, the San Antonio Water Company has controlled the water rights in San Antonio Canyon, including its three hydroelectric plants. A tributary of San Antonio Creek flows through what

5312-404: The first recorded ascent to the mountain's summit, via Lytle Creek, and estimated the height of the peak. In 1880, W.H. Stoddard, brother-in-law of railroad baron Collis P. Huntington , built a resort in what is now called Stoddard Canyon. Frank Keyes converted Dell's Camp from a mining support station into a rental resort. Early mountain guide William B. Dewey led parties of guests to the summit on

5395-731: The following year the canyon became accessible by automobile. In 1910, Dewey built the Baldy Summit Inn, 80 feet below the mountaintop. Despite the grand name, it consisted of only a set of tents and some storage buildings. It was damaged by a cooking fire in 1913 and never rebuilt. By the early 1920s there were numerous trail camps and resorts such as the Icehouse Canyon Resort, Bear Canyon Resort Eleven Oaks, Baynham Camp, Alpine Woods, Trail Inn, Snow Crest, and Kelly's Camp. The shift from exploitation of natural resources to recreational use of San Antonio Canyon resulted in

5478-556: The highest peak in the San Gabriel Mountains range. The stream flows southwest through San Antonio Canyon and past Mount Baldy Village , then south, winding through the Angeles National Forest . At the end of the canyon it reaches the San Antonio Dam , but after passing through the dam, the stream is usually dry. It flows south through a concrete flood control channel , passing through the several cities of

5561-473: The initiation of the modern basin. This movement caused the southwestern block to be uplifted relative to the central basin block. The central part of the basin continued to experience sediment deposition through the Pleistocene from flooding and erosional debris from the surrounding mountains and Puente Hills. This infill was responsible for the final retreat of the shoreline from the basin. Deposition in

5644-490: The land, "Baldy" – a reference to the bare fell-field of Baldy Bowl that dominates the south face visible from Los Angeles – became the predominant name, and it has stuck. Nonetheless, "Mount San Antonio" is still used by a number of institutions (e.g. Mount San Antonio College ). Mt. San Antonio lies in the Angeles National Forest . Its summit is 10,064 feet (3,068 m), and marks the boundary between San Bernardino County and Los Angeles County . A sub-peak, West Baldy,

5727-444: The late Pliocene. Until the rate of deposition gradually overtook the rate of subsidence, and the sea level began to fall. Towards the end of this phase, the margins of the basin began to rise above sea level. During the early Pleistocene, deposition began to outpace subsidence in the depressed parts of the basin and the shoreline began to move southward. This phase also had movement along the Newport–Inglewood fault zone that resulted in

5810-469: The parking lot at Icehouse and goes all the way up to Icehouse Saddle where a number of trails can be taken either to the Notch or to nearby peaks such as Ontario and Cucamonga. (5.5 miles). Ski Hut Trail – This trail follows the east side of the San Antonio Creek canyon to a small backcountry ski hut owned by the Sierra Club. A use trail continues around the left side of the bowl and then to

5893-554: The road from 1908 to 1922. The camp was renamed Camp Baldy in 1910. When the area became a national forest in 1908, the forest service began offering 99-year leases of plots of land in Icehouse Canyon for vacation cabins. By 1938 there were 105 cabins and additional cabins at a resort owned by the Chapman family. Leases were also sold, both by the government and by the water company, at Camp Baldy and Manker Flat. Between 1922 and 1927 American physicist Albert A. Michelson performed

5976-419: The south side and the desert side of the range. Merriam's chipmunk ( Neotamias merriami ) inhabits the San Gabriels in low-elevation areas containing manzanita, below the yellow pine forest community. Rodents found at higher elevations in the San Gabriels include lodgepole chipmunks ( Neotamias speciosus ), all the way up to the tree line, and the California ground squirrel ( Otospermophilus beecheyi ) in

6059-718: The southeast, the basin is bordered by the Santa Ana Mountains and the San Joaquin Hills . The western boundary of the basin is marked by the Continental Borderland and is part of the onshore portion. The California borderland is characterized by northwest trending offshore ridges and basins. The Los Angeles Basin is notable for its great structural relief and complexity in relation to its geologic youth and small size for its prolific oil production. Yerkes et al. identify five major stages of

6142-553: The state flag, were once common in the Transverse Ranges, but were driven to extinction in California in the late 19th century, with one of the last animals in the San Gabriels being shot in 1894 by Walter L. Richardson. Black bears ( Ursus americanus ) did not naturally exist in the San Gabriel Mountains, but in 1933 eleven black bears from Yosemite Valley that had shown problematic behavior were moved to Southern California and released near Crystal Lake. All black bears in

6225-500: The strata present and major structural features. The southwestern block was uplifted prior to the middle Miocene and is composed mostly of marine strata and contains two major anticlines. This block also contains the steeply-dipping Palos Verdes Hills fault zone. The middle Miocene volcanics can be seen locally within the southwest block. The northwestern block consists of clastic marine sediments of Late Cretaceous to Pleistocene age. Middle Miocene volcanics are also present. This block has

6308-526: The summit. Three T’s – (5.3 miles one way): The trail starts and ends at the Icehouse Canyon Trailhead. It leads to views from the summits of Thunder, Timber and Telegraph Mountains. North Backbone Trail – (6.9 miles one way): The trail is a use trail that starts near Wrightwood but also near Wright Mountain. The trailhead is on a dirt road near Blue Ridge on CA-2. It summits 2 peaks: Dawson Peak and Pine Mountain. For mountaineers,

6391-480: The water was released catastrophically, forming a slot canyon which now holds some of the area's few good rock climbing routes (difficulty 5.11, sport). In modern times, notable floods have occurred in 1938 and 1969. The San Antonio Dam was completed in 1956, after a pause due to World War II , in an effort to prevent future floods as severe as the one in 1938, which damaged the low-elevation, highly populated areas below. The dam succeeded in significantly reducing

6474-412: The winter and spring offer a snow climbing challenge. The " Baldy Bowl " south of the summit is often climbed with crampons and ice ax , depending on snow conditions. The bowl can be treacherous for inexperienced climbers as some sections have slopes of 45° to 50°. Avalanches and rock fall are both hazards, and deaths or rescues from accidents along Devil's Backbone are a common occurrence. There are also

6557-406: The yellow pine forest community gives way to a pure lodgepole forest. Near 9,000 ft (2,750 m) these become increasingly krummholzed , and beyond about 9,500 ft (2,900 m) lies an unforested alpine zone . Mountain mahogany trees grow on the slopes above San Antonio Creek. The dominant shrubs at the higher elevations are manzanita and bush chinquapin . As the elevation increases, there

6640-406: The yellow pine forest on the south side of the range. They hibernate in winter. Rabbits may also occasionally be observed at high elevations. The two species of chipmunk are difficult to distinguish visually, and firm identification may require examination of their pubic bones, but the lodgepole chipmunk has brighter white stripes. It is easier to distinguish the western gray squirrel (gray, with

6723-488: Was accompanied with the rotation of the western Transverse Ranges. This rotation is responsible for the placement and northwest–southeast orientation of the LA Basin. Early in the Miocene, before deposition of the Topanga, high heat flow and transtension caused the extension of the basin. As the crust thinned, the basin began to subside from isostatic pressure as a result of large amounts of sediment deposition. Because

6806-598: Was immediately replaced and remains standing today. The flood of 1938 destroyed most of the human-made structures in Camp Baldy and Icehouse Canyon. The casino was destroyed, but the hotel (today's Buckhorn Lodge) survived. No new building has been allowed in Icehouse Canyon, and the Icehouse Canyon resort was destroyed in 1988 by a suspicious fire. Camp Baldy was rebuilt and later became Mt. Baldy Village. Los Angeles Basin The Los Angeles Basin

6889-495: Was later mayor of Los Angeles.) Gold mining did not begin in the area until decades after the California Gold Rush , with the earliest historical record being of the death of miner Jacob Skinner in 1879 in his mine at the Hog Back slide. Placer mining gave way to hydraulic mining in the 1880s and continued through the 90's. The Banks (Hocumac) Mine was built in 1893 near the Baldy Notch. It was supplied with water by

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