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Changing Sea Levels: The Ice Age Island Sculpting Story

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Part 2

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Changing Direction: The Island and Mountain Formation Story

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Part 1

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Changing Plates: The Tectonic Story (85 to 20 million years ago)

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Channel Islands Geologic Formations Overview

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Channel Islands Geologic Formations Overview

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A cemented sand dune at Carrington Point on Santa Rosa Island
Randall Schumann, USGS

Sedimentary Rocks
Many of the rocks of the northern Channel Islands are sedimentary, made up of sediment washed out to sea from the mainland, reworked volcanic deposits, and shells and skeletons of marine organisms. Much is shale, deposited as mud, but there is also sandstone that formed by sand being swept out to sea from the mainland in huge submarine landslides.

Not all the sedimentary rocks were deposited below the surface of the ocean, however. As the last piece of the Farallon plate was subducted beneath the continent, the East Pacific Rise - an under-sea mountain range that separated the Farallon plate from the Pacific plate - came into contact with the North American plate. This probably led to an uplift of the area and the deposit of sediment in an alluvial plane, much like the present alluvial plain of the Santa Clara river in the Oxnard-Ventura area. The pink-colored rocks of the Sespe Formation were deposited about 30 million years ago in this uplifted area. Iron-rich minerals in terrestrial environments commonly are oxidized, giving them red, orange and yellow colors. This period of uplift was short lived, however, because the later sediments, which date between 25 and 5 million years ago, were deposited first in shallow marine environments, then in progressively deeper marine settings.

Analysis of some of the sedimentary rocks provide additional evidence that the islands have rotated 100 degrees clockwise from their original position adjacent to the coast. On San Miguel Island, rocks dating 50-30 million years ago contain well-rounded pieces of rhyolite that are chemically identical to the rhyolite found in similar age deposits in San Diego county. The inference is that these pieces of rhyolite reached the islands in a submarine fan deposit when the islands were positioned off the coast of San Diego. Analysis of the direction of the currents flowing at that time shows that they came from a southerly direction. However, the only possible source of these sediments is from the mainland, which lies to the east of the islands, giving geologists one more reason to believe that the islands have rotated 90-100 degrees in the last 20 million years.

Uplift of the Islands--Folding and Faulting
The last of the marine rocks are only about five million years old, so we know that the islands must have started to rise after that time. The northern Channel Islands, together with the Santa Monica Mountains and the Coast Range, rose because of compressional forces connected with an event in the geologic history of the area that took place five million years ago. At that time, the Pacific plate captured Baja California and began transporting it northwestward, ramming its northern end into southern California. Transtension ceased, and the resulting compression caused folding and faulting of the rocks and the uplift of the islands. There are large faults running through the centers of Santa Cruz and Santa Rosa Islands. These major faults are marked by valleys, owing to rocks in the fault zone being crushed and eroding more easily. Lateral and vertical movement along these faults have made the surface features of the north and south parts of those islands appear to be quite dissimilar. These compressional forces are still on-going and make this area of California an active earthquake area. In 1812, a large earthquake, centered in the Santa Barbara Channel, caused landslides on the islands and is often cited as the reason that the last of the Chumash Indians were persuaded to leave the islands and relocate at the mission in Santa Barbara. The 1925 Santa Barbara; 1971 Sylmar; and the 1994 Northridge earthquakes are all related to these compressive stresses.

One Large Island During the Ice Ages; Mammal Fossils and Marine Terraces
Even in comparatively recent times, the islands have not always looked as they do today. During the last Ice Age, which lasted until about ten thousand years ago, sea level was about 400 feet lower than it is today. The four northern islands that are now separated by water were once connected into one large island, which geologists have named 'Santa Rosae', the nearest point at that time being about five miles from the mainland. Large Columbian mammoths swam to Santa Rosae island and soon, because of isolation and dwindling food supplies, became much smaller. Evidence of these animals has been found as fossils of pygmy mammoths on the islands of Santa Cruz, Santa Rosa, and San Miguel.

Because of the continuing uplift of the islands during the last million years and the fluctuating sea level caused by glacial advances and retreats, there is evidence on the islands of ancient shorelines at different elevations. The rise in sea level over the last 10,000 years has caused many of the ancient shorelines to be lost below sea level, but others remain. These ancient shorelines form flat areas of land, called marine terraces. Marine terraces are found at many different elevations, from 20 feet above sea level to as much as 1000 feet above, giving graphic evidence of how the islands have changed in their configuration over time.

Erosion
Weathering and erosion are natural geologic processes that gradually change the look of the landscape, as rocks are broken up into smaller particles that are carried away by rivers and wind to be deposited elsewhere as sand and gravel. Erosion is slow in areas covered by vegetation and rapid where ground cover is depleted. There were two periods when erosion on the islands was greatly increased. During one of these periods, 15,000 to 10,000 years ago, there was extensive stripping of vegetation by mammoths. One possible reason for mammoth extinction may be this denuding of vegetation. Much more recent is the extensive erosion caused by sheep, cattle, and other feral animals which were introduced on most of the islands over one hundred years ago. During times of food shortage, probably caused by years of drought, sheep ate not only all accessible vegetation, but they also ate the roots. During these periods of denudation, both ancient and modern, the land stripped of its cover eroded very quickly, forming steep canyons through the hillsides and increased deposition of sand on the beaches. Fierce winds, common on the northern islands, blow the beach sand over the island -- and the beaches were more extensive during the Ice Age - resulting in vast areas of the islands being covered by sand. In recent times, the erosion caused by sheep on San Miguel island transformed the island into little more than one huge sand dune.

The good news is that the islands have recovered their vegetation where the animals have been removed. On San Miguel Island, which has been sheep free for over forty years, vegetation has spread from the steep canyons, where it was able to survive during the grazing years, and has now recovered nearly the entire island, restoring the island's natural beauty. More recently, sheep and pigs have been removed from Santa Cruz Island, so we can look forward to a similar reversal of the extensive erosion that is currently in evidence on hillsides there.

Caliche
Visitors to San Miguel Island have the opportunity to view the caliche 'forest', where the root system of vegetation that grew on the island several hundred years ago has been turned into caliche casts and caliche root sheaths

Caliche Casts: Caliche is calcium-carbonate cemented soil that is formed in semi-arid climates. Calcium carbonate is derived by the dissolution of shells and shell fragments that have blown across the island from the beaches, especially during the Ice Age when the sea level was much lower and the beaches were more extensive. Rain is a weak acid, formed by reactions between water vapor and carbon dioxide in the atmosphere, and it is this acid that dissolves the shell fragments. San Miguel has a semi-arid climate; so when it rains, the volume of water is too small to carry dissolved materials away from the area, and they remain in the topsoil. This groundwater dissolves the calcium carbonate from shells in the surface layer and re-precipitates it a little lower in the surface profile, where it will act as a cement, binding the soil material into a hard substance that is called 'caliche', or 'calcrete', or 'hardpan'.

On San Miguel Island, the deep root system of trees that grew several hundreds of years ago decomposed, and the molds of the roots filled with the abundant sand that makes up much of the topsoil of the island. The calcium carbonate preferentially cemented the sand-filled molds, possibly because they were more porous and provided an easy pathway for the groundwater.

Caliche Root Sheats: Another form of caliche is where living vegetation, generally a root in the soil, gets a 'sheath' of caliche. The living roots may exude a weak acid, or draw soil moisture towards them by capillary action. In either case, a solution of calcium carbonate from the soil is concentrated around the roots which, when precipitated later, forms a sheath of caliche. When the root dies and rots, the sheath will remain, either as a hollow form, or may be filled with sand, which may become a caliche cast, by the method described above. Many such examples of both hollow forms and filled sheaths can be found on San Miguel Island.

The caliche 'forest' of San Miguel Island was created when strong winds blew away the uncemented sandy soil surrounding the caliche casts and the root sheaths. The visitor to San Miguel Island is treated to this rare glimpse of a landscape turned inside out -- the roots and lower trunks of these ancient plants now stand as 'forests'.

Chert
The mineral chert is an extremely hard material that is found in many places on the islands. Whereas caliche is derived from calcium carbonate in shells, chert forms from very small sea plants, called diatoms, which are made from opaline silica, silicon dioxide. The process by which chert was formed probably took place in the mud at the bottom of the ocean which contained very large numbers of siliceous diatoms and small amounts of calcium carbonate shells and fish bones. Water dissolved some of the silica, which later precipitated out in the form that is called chert. Eventually the mud solidified to form a shale rich in diatoms, with nodules of very hard chert in places. Chert fractures like glass and was used by the Chumash Indians for arrowheads and scraping and cutting tools. Chert on the islands has a light brown color, owing to small amounts of iron impurities. Impurities in chert give it a variety of colors. The black variety is called flint and is colored by inclusions of organic matter. Jasper is the name given to the red-colored variety and is colored by inclusions of an iron oxide mineral, hematite.

The Geologic Future of the Islands
The current compressional regime in our area is expected to last until the San Andreas Fault straightens out from its present bent shape, which might take a few million years. During that time, the islands will continue to rise as uplift continues to be greater than erosion. Earthquakes will continue to be felt, both on the islands and on the mainland. When compression ends, erosion will be the main force, and the islands will gradually erode into the ocean.

Sea level will rise and fall as ice ages come and go. At some times the islands will again be one, as they were during the last ice age. New marine terraces will be cut into the islands.

Acknowledgements and Further Reading
The information above was written by volunteer George Roberts. Much of what was written here was taken from articles by Tana M. Atwater; John J. Woolley; Thomas W. Dibblee Jr., and Helmut E. Ehrenspeck in Weigand P. W., editor, 1998, Contributions to the Geology of the Channel Islands, Southern California, Pacific Section American Association of Petroleum Geologists, Miscellaneous Publication 45, 196 p.

CSUN Department of Geological Sciences professors: Peter W. Weigand, A. Eugene Fritsche, and Vicki Pedone read a preliminary text and provided many valuable comments.

Additional reading:

Howell, D. G. ed., 1976, Aspects of the geologic history of the California Continental Borderland; American Association of Petroleum Geologists, Pacific Section, MP 24, 558 p.

Weaver, D. W., Doerner, D. P., and Nolf, B., eds., 1969, Geology of the Northern Channel Islands; American Association of Petroleum Geologists and Society of Economic Paleontologists and Mineralogists, Pacific Sections, Special Publications, 200 p.

Geologic maps of Santa Rosa Island and San Miguel Island are published by the Dibblee Geological Foundation and may be purchased at the Santa Barbara Natural History Museum.

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Geologic Formations - Channel Islands National Park (U.S. National Park Service)

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Sedimentary Rocks Many of the rocks of the northern Channel Islands are sedimentary, made up of sediment washed out to sea from the mainland, reworked volcanic deposits, and shells and skeletons of marine organisms. Much is shale, deposited as mud, but there is also sandstone that formed by sand being swept out to sea from the mainland in huge submarine landslides.

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What are the Transverse Ranges?

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The Transverse Ranges are a group of mountain ranges of southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa Barbara, Ventura, Los Angeles, San Bernardino, Riverside and Kern counties. The Peninsular Ranges lie to the south. The name Transverse Ranges is due to their east-west orientation, making them transverse to the general northwest-southeast orientation of most of California's coastal mountains.

The ranges extend from west of Point Conception eastward approximately 500 kilometers into the Mojave and Colorado Desert. The geology and topography of the ranges express three distinct segments that have contrasting elevations, rock types, and vegetation. The western segment extends to the San Gabriel Mountains and San Gabriel fault. The central segment includes mountains that range eastward to the San Andreas fault. The eastern segment extends from the San Andreas fault eastward to the Colorado Desert. The central and eastern segments (near the San Andreas fault) have the highest elevations.

Most of the ranges lie in the California chaparral and woodlands ecoregion. Lower elevations are dominated by chaparral and scrubland, while higher elevations support large conifer forests. Most of the ranges in the system are fault blocks, and were uplifted by tectonic movements late in the Cenozoic Era. West of Tejon Pass, the primary rock types are varied, with a mix of sedimentary, volcanic, and metamorphic rocks, while regions east of the pass are dominated by plutonic granitic and metasedimentary rocks.

The western and central segments of the Transverse Ranges are bounded to the north and east by the San Andreas Fault, which separates those segments from the Mojave Desert. The eastern segment bounds the southern Mojave Desert. Notable passes along the San Andreas fault include Tejon Pass, Cajon Pass, and San Gorgonio Pass. Components of Transverse Ranges to the north and east of the fault include the San Bernardino Mountains, Little San Bernardino Mountains, Pinto and Eagle Mountains. The western and southern boundaries are acknowledged to be the Pacific Ocean and the northern Channel Islands. Onshore the Los Angeles Basin lies at the southern boundary of the western and central segments of the ranges. Major passes not along the San Andreas Fault include Gaviota Pass, San Marcos Pass, the Conejo Grade, Newhall Pass, and Cahuenga Pass.

The Transverse Ranges manifest themselves as a series of roughly parallel ridges with an average height of 3,000-8,000 feet (910-2,440 m). The ranges are dissected by young, steep streams of relatively low flow rate; as a result, there is high topographic relief throughout the range, and other than in marginal areas (e.g. the San Fernando Valley) and a few river valleys (such as Lockwood Valley and Big Bear Valley), there are no large, flat basins within the ranges.

The mountains are notable for being steep and difficult to traverse. There are few passes that are sufficiently low or wide enough to accommodate significant volumes of traffic. This has resulted in situations where major cities are linked to the rest of the state by relatively few roads; for example, the vast majority of traffic between the Central Valley and the Los Angeles area is routed through Tejon Pass. This results in significant traffic issues throughout Southern California when a pass has to be shut down due to heavy snow or construction. Occasionally, major cities, such as Santa Barbara during the 2005 La Conchita landslide, may be cut off from timely road access to the rest of Southern California.

Major peaks of the Transverse Ranges with at least 500 feet (150 m) of prominence, listed by height:

1. Mount San Gorgonio, 11,503 feet (3,506 m), San Bernardino Mountains.

2. Anderson Peak, 10,840 feet (3,300 m), San Bernardino Mountains.

3. Mount San Antonio (Old Baldy), 10,068 feet (3,069 m), San Gabriel Mountains.

4. Sugarloaf Mountain, 9,952 feet (3,033 m), San Bernardino Mountains.

5. Mount Baden-Powell, 9,407 feet (2,867 m), San Gabriel Mountains.

6. Galena Peak, 9,324 feet (2,842 m), San Bernardino Mountains.

7. Throop Peak, 9,142 feet (2,786 m), San Gabriel Mountains.

8. Telegraph Peak, 8,985 feet (2,739 m), San Gabriel Mountains.

9. Cucamonga Peak, 8,862 feet (2,701 m), San Gabriel Mountains.

10. Mount Pinos, 8,847 feet (2,697 m).

11. Ontario Peak, 8,693 feet (2,650 m), San Gabriel Mountains.

12. Delamar Mountain, 8,402 feet (2,561 m), San Bernardino Mountains.

13. Cerro Noroeste, 8,280 feet (2,520 m).

14. Mount Islip, 8,254 feet (2,516 m), San Gabriel Mountains.

15. Gold Mountain, 8,239 feet (2,511 m), San Bernardino Mountains.

16. Bertha Peak, 8,205 feet (2,501 m), San Bernardino Mountains.

17. Frazier Mountain, 8,017 feet (2,444 m).

18. Iron Mountain #1, 8,010 feet (2,440 m), San Gabriel Mountains.

19. Reyes Peak, 7,510 feet (2,290 m), Pine Mountain Ridge.

20. Haddock Mountain, 7,431 feet (2,265 m), Pine Mountain Ridge.

Western segment

This segment begins at Point Conception in Santa Barbara County, and include the Santa Ynez Mountains that run parallel to the coast behind Santa Barbara. The western Transverse Ranges also include the Topatopa Mountains and the Santa Susana Mountains of Ventura County and Los Angeles County, the Simi Hills, the Santa Monica Mountains that run along the Pacific coast behind Malibu, and whose eastern portion are known as the Hollywood Hills, and the Chalk Hills. The northern Channel Islands of California are also part of the Transverse Ranges; San Miguel, Santa Rosa, Santa Cruz and Anacapa Islands are a westward extension of the Santa Monica Mountains.

Central segment

The Ranges include the steep San Gabriel Mountains northeast of Los Angeles, the Tehachapi Mountains southeast of Bakersfield, the Verdugo Mountains, the Liebre-Sawmill Mountains, the San Rafael Hills, Puente Hills, San Jose Hills, and Chino Hills.

Eastern segment

The San Bernardino Mountains, Little San Bernardino Mountains, and the Pinto, Eagle, and Orocopia Mountains are within the eastern segment. The Mojave Desert and California's low desert, including the Coachella Valley, are at the eastern end of the ranges.

Ranges north of the western segment that are nearly transverse but are part of the California Coast Ranges include the San Rafael Mountains and the Sierra Madre Mountains. Likewise, the Tehachapi Mountains north of the Mojave Desert, although nearly transverse, are the southern end of the Sierra Nevada.

The climate in most of the range is Csb ( Warm-summer Mediterranean) under the Köppen climate classification; the upper reaches of San Gorgonio Mountain have an alpine tundra climate ( ET), while the lower northern slopes of the range have a desert ( BW) or steppe ( BS) climate; most of the nearby lowlands to the south and west have a Hot-summer Mediterranean climate ( Csa).

Snow falls above 6,000 feet (1,800 m) most winters, and above 3,000 feet (910 m) every few years. It is rare for elevations above 8,000 feet (2,400 m) to go multiple winters without snow, even during severe droughts. Due to relatively low humidity, the regional snow line lies at about 14,000-16,000 feet (4,300-4,900 m), above the highest elevation of the range; as such, snow does not persist year-round except in the form of snow patches.

The tree line lies at about 11,000 feet (3,400 m); San Gorgonio Mountain is the only peak with an alpine environment.

The Transverse Ranges result from a complex of tectonic forces and faulting stemming from the interaction of the Pacific Plate and the North American Plate along the dextral (right slip) San Andreas Fault system. Their orientation along an east-west axis as opposed to the general northwest-southeast trend of most California ranges results from a pronounced left step in the San Andreas Fault that occurred in the Pliocene ( c. 4 million years ago) when southern reaches of the fault moved east to open the Gulf of California. The crust within the Pacific Plate south of the ranges can not easily make the left turn westward as the entire plate moves northwestward, forcing pieces of the crust to compress and lift.

Prior to this shift of the fault to create the left bend, northwest-southeast trending rock belts in all of the Transverse Ranges began to rotate clockwise in the right shear of Pacific Plate - North American Plate motion. This tectonic rotation began in Early Miocene Time and continues today. The total rotation is about 90° in the Western Transverse Ranges and less (about 40°) in the eastern ranges. Catalina Island shows the most rotation: almost 120°.

A mechanism proposed for the rotation event is capture of the subducting Monterey plate by the outboard Pacific plate. Because the Monterey plate was then beneath southern California, the capture resulted in pulling of the overlying crust out and northward from the rest of California.

Rocks of the Transverse Ranges exhibit extreme differences in geologic age and composition, varying from sedimentary rocks in the western Santa Ynez and volcanic rocks in the Santa Monica Mountains to primarily granitic and metamorphic rock in the central and eastern segments, including the San Gabriel and San Bernardino Mountains.

The oldest basement (deepest) rocks are of Proterozoic age, and are found in the San Gabriel Mountains and the San Bernardino Mountains. The Jurassic- Cretaceous Franciscan Assemblage is found in the western section of the ranges and is the presumed basement in this segment. Exposed plutonic rocks from the Mesozoic, mostly granites, can be found on Mount Pinos and generally in regions east of Tejon Pass. The youngest rocks are Cenozoic sedimentary and volcanic rocks that can be found throughout the ranges.

The western segment is distinctive for the large thickness of Cretaceous and Cenozoic sedimentary rocks, estimated to be up to 10 kilometers. The thickest deposits of these are in the Santa Barbara Channel and Ventura basin. These are mostly marine in origin with a marked change to red beds of river systems of Oligocene age in the western and central segments.

Limestones and dolomites of the marine Miocene Monterey Formation are found in the Santa Ynez Mountains and in the Coast Ranges to the north.

The distinctive feature of the Transverse Ranges besides their anomalous orientation is that they are bounded by east-west trending faults. Most are left slip, strike slip faults. In the western and central segments many of the faults are thrust faults. Faults in the Coast Ranges and Peninsular Ranges trend northwest-southeast and butt into the east-west trending faults of the Transverse Ranges. Because all of these faults are considered active and seismic but they do to cut each other, the only geometry that satisfies that observation is if the east-west faults and Transverse Ranges are rotating clockwise with respect to the faults outside that province.

Between the western segment and the Peninsular Ranges to the south is the complex Malibu Coast-Santa Monica- Hollywood fault, which exists as the border between these two mostly geologically unitary provinces. These faults are part of the same thrust fault system south of the northern Channel Islands of San Miguel, Santa Rosa, and Anacapa Islands. North of the western segment the bounding faults are left slip Santa Ynez and Pine Mountain Faults. The San Gabriel Fault and San Andreas bound the central segment. The eastern segment is bounded by the Pinto Mountain Fault in the north and the Salton Creek Fault in the south.

The large thickness of marine sediments in the western segment have made it a habit for oil. Several dozen fields are found onshore and offshore, particularly in the Santa Barbara Channel and Ventura Basin. Much oil has pooled in the Monterey Formation, which is produced onshore and offshore. In the eastern Santa Barbara Channel oil is held in younger sedimentary rocks. The Los Angeles Basin south of the western segment, formed during rotation of that segment away from the Peninsular Ranges. It is also a site of prolific oil production. The California Geologic Survey states:

Great thicknesses of Cenozoic petroleum-rich sedimentary rocks have been folded and faulted, making California one of the most important oil-producing areas in the United States.

The plant place of the Transverse ranges include coastal sage scrub, oak woodland and savanna, and pinyon-juniper woodland at lower elevations, and yellow pine forest, Lodgepole Pine, and subalpine forest at higher elevations. The Angeles and Los Padres National Forests cover portions of the Transverse ranges. The ranges are part of the WWF-designated California montane chaparral and woodlands ecoregion, but the eastern points of the range touch two desert regions, the Mojave Desert and the Colorado Desert section of the Sonoran Desert. The Carrizo Plain adjoins the northern edge of the Transverse Range.[citation needed ]

Chaparral is a common feature of the Transverse Ranges. Common plant associates in chaparral, especially in the transition between coastal chaparral and coastal sage scrub, include California sagebrush and Toyon, the latter shrub having its southern distribution limit defined by the Transverse Ranges.

Pinyon-juniper woodland is common on the north slopes of the San Gabriel and San Bernardino Mountains. This ecosystem is easily visible in the well-travelled Soledad Pass region, between Pearblossom and Santa Clarita.[citation needed ]

A number of densely populated coastal plains and interior valleys lie between the mountain ranges, including the Oxnard Plain of coastal Ventura County, the Santa Clarita Valley north of Los Angeles, the San Fernando Valley, which is mostly included in the City of Los Angeles. The Los Angeles Basin, which includes the portion of Los Angeles County south of the Santa Monica Mountains and most of Orange County, and the Inland Empire basin, which includes the cities of San Bernardino and Riverside, lie between the Transverse Ranges and the Peninsular Ranges to the south.[citation needed ]

There are a number of important freeways that cross the Transverse Ranges, such as (from west to east) US-101, I-5 at Tejon Pass, SR 14 at Soledad Pass, and I-15 at Cajon Pass. These highways link Southern California with places to the north and northeast like San Francisco and Las Vegas, respectively. With the exception of several high passes on less-traveled SR 33, SR 2, SR 330. SR 18 and SR 38, none of these passes are at high elevations, with Cajon Pass being at a modest 4,190 ft (1,277 m) above mean sea level; this means that snow is less of a factor here than in the moderate to high mountain passes to the north like Donner Pass. Still sometimes, heavy snowfall can snarl traffic on Tejon and Cajon Pass, the higher two of the three freeway passes. I-5 and I-15 commonly experience heavy traffic over their mountainous route across these mountains.[citation needed ]

U.S. Geological Survey (1987). "Recent reverse faulting in the Transverse Ranges, California". USGS Publications Warehouse. Washington, D.C.: United States Geological Survey. doi:10.3133/pp1339.

Minor, S.A., Kellogg, K.S., Stanley, R.G., Gurrola, L.D., Keller, E.A. and Brandt, T.R., 2009. Geologic map of the Santa Barbara coastal plain area, Santa Barbara County, California: US Geological Survey Scientific Investigations Map 3001, scale 1: 25,000, 1 sheet, pamphlet 38 p.

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The Transverse Ranges are a group of mountain ranges of southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa Barbara, Ventura, Los Angeles, San Bernardino, Riverside and Kern counties.