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75-586: The Black Diamond Mines Regional Preserve is a 6,000-acre (2,400 ha) park located north of Mount Diablo in Contra Costa County, California under the administration of the East Bay Regional Park District (EBRPD). The district acquired the property in 1973. The preserve contains relics of 3 mining towns, former coal and sand mines, and offers guided tours of a former sand mine. The 60 miles (97 km) of trails in

150-463: A Protestant cemetery, the final resting place for over 200 residents of the coalfield, is located on a hillside between the Somersville and Nortonville townsites. After the mines closed and the nearby towns were abandoned, the cemetery fell into disuse. Many of the gravestones were stolen or destroyed by vandals. In 1960, Ansel Adams photographed two Italian Cypress trees in the cemetery, and called

225-752: A clear day, the Sierra Nevada range is plainly visible from the summit. The best views are after a winter storm; a snowy Sierra shows up better, and summer days are likely to be hazy. Lassen Peak , 181 miles (291 kilometers) away, is occasionally just visible over the curve of the earth. Sentinel Dome in Yosemite National Park is visible, but Half Dome is hidden by the 8000-foot ridge at 37.755N 119.6657W. Eight bridges are visible, from left to right (southwest to northeast): San Mateo , Bay , Golden Gate , San Rafael , Carquinez , Benicia , Antioch , and Rio Vista . Countless peaks in

300-467: A gated residential community there when he had bought the tract in 1987. After going through an extensive permitting process and a decline in the California housing market, Grevelle decided that the project he had envisioned would be unlikely to meet his financial goals. Since the tract was already surrounded by park land, he chose to make the land available to EBRPD, which announced its intention to add

375-412: A mate. These spiders are harmless unless severely provoked, and their bite is only as bad as a bee sting. More dangerous are black widow spiders , far less likely to be encountered in the open. In the wintertime, between November and February, bald eagles and golden eagles are present. These birds are less easily seen than many raptors; golden eagles, particularly, fly at high elevations. Mount Diablo

450-637: A willow thicket some 7 miles north of the mountain. One story tells that their nighttime escape through the thicket was aided by mysterious lights. An 1850 report by General Mariano G. Vallejo tells of a strange dancing spirit turning the battle in favor of the Chupcan. Vallejo interpreted the natives' word for the personage, puy , to mean "devil" in the Anglo-American language. Vallejo's report could be interpreted to align with Edward G. Gudde's history of place names. (Kyle, and Ortiz) By 1824,

525-489: Is a living person, and so is banned under federal law. He suggested renaming the mountain Mount Kawukum, and later, Mount Yahweh . Suggestions by other individuals included Mount Miwok and Mount Ohlone , after local Indian tribes. Finally Mijares proposed Mount Reagan , but the board rejected it on the grounds that a person must be deceased for five years to have a geographic landmark named after them. Eventually,

600-797: Is administered by California State Parks . The summit is accessible by foot, bicycle, or motor vehicle. Road access is via North Gate Road or South Gate Road. The peak is in Mount Diablo State Park, a state park of about 20,000 acres (8,000 hectares). The state park was the first public open space established on or near the peak. According to the non-profit Save Mount Diablo, there are now varied types of protected lands on and around Mount Diablo that total more than 90,000 acres (36,000 ha). These include 38 preserves, such as nearby city open spaces, regional parks, and watersheds , which are buffered in some areas with private lands that have been protected by conservation easements . On

675-538: Is also known as Southgate. If the entrance stations are not operating, park fees may be paid at the junction ranger station, where the two roads join. From here the road reaches the summit of the mountain, where there is a visitors center housing an observation deck and natural history exhibits. From the elevation of the lower lot the Mary Bowerman Trail is a level wheelchair-accessible path and boardwalk with interpretive stations that extends part way around

750-470: Is best to learn the characteristics of this shrub and its toxin before hiking on narrow trails through brush and to be aware that it can be bare of leaves (but toxic to contact) in the winter.) At higher altitudes and on north slopes is the widely distributed foothill pine ( Pinus sabiniana ). Knobcone pine ( Pinus attenuata ) may be found along Knobcone Pine Road in the southern part of the park. The park and nearby Black Diamond Mines Regional Preserve mark

825-530: Is forbidden in the park. Fires are allowed only during the wet season (generally December through April), and only in sanctioned fire pits. The park may be closed on windy days during the dry season due to extremely hazardous fire conditions. Two additional entrances with parking for hikers are provided on the northwest side of the park at Mitchell Canyon and Donner Canyon. Mitchell Canyon provides easy access to Black Point and Eagle Peak. Donner Canyon provides hikers access to Eagle Peak, Mount Olympia, North Peak, and

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900-571: Is not an appropriate name for the historic mountain. Later, the board unanimously voted against renaming the mountain, citing its historical significance. In 1851 the south peak of the mountain was selected by Colonel Leander Ransom as the initial point —where the Mount Diablo Base and Mount Diablo Meridian lines intersect—for cadastral surveys of a large area. Subsequent surveys in much of California , Nevada and Oregon were located with reference to this point. Toll roads up

975-739: Is now part of the Black Diamond Mines Regional Preserve . Nortonville was founded by Noah Norton in 1855. He, along with three partners named Cutler, Matheson and Sturgis, started the Black Diamond coal mine at Nortonville in 1860. The mine was incorporated as the Black Diamond Coal Mining Company in June 1861. Nortonville was also the southern terminus of the six mile long Black Diamond Coal Mining Railroad (also known as

1050-449: Is open year-round for hiking, mountain biking, and horseback riding from 8 am to dusk. A backpack camp and a group camp can be reserved for overnight stays. There have been many reports of a ghost in the park. EBRPD accepted the donation of 50 acres (20 ha) by Antioch Holdings LLC on December 20, 2016. The property had been deeded to the holding company by Gordon Grevelle, president of Suncrest Homes, who had originally planned to build

1125-690: Is part of the Altamont Area/Diablo Range, which enjoys the largest concentration of golden eagles anywhere. In recent years there have been credible sightings of California condors, which have been reintroduced at Pinnacles National Park, located to the south in the Gilroy-Hollister area. Of special note as potential hazards are Northern Pacific rattlesnake . While generally shy and non-threatening, one should be observant and cautious of where one steps to avoid accidentally disturbing one. They are often found warming themselves in

1200-631: The East Bay Regional Park District , including Morgan Territory Regional Preserve , Brushy Peak Regional Preserve , Vasco Caves Regional Preserve , and Round Valley Regional Preserve . It also adjoins protected areas owned or controlled by local cities such as the Borges Ranch Historic Farm , the Concord Naval Weapons Station (now in the process of being converted to non military use), Indian Valley, Shell Ridge Open Space and Lime Ridge Open Spaces near

1275-664: The Great Valley Sequence were deposited from 66 to 150 million years ago. These deposits are now found faulted against the Ophiolite and Franciscan deposits. Over the past 20 million years continental deposits have been periodically laid down and subsequently jostled around by the newly formed San Andreas Fault system, forming the Coast Ranges. Within the last four million years, local faulting has resulted in compression, folding, buckling, and erosion, bringing

1350-672: The Sierra Nevada . The Preserve usually has an impressive variety of wildflowers in spring including the rare Mount Diablo fairy lantern ( Calochortus pulchellus ), Mount Diablo sunflower ( Helianthella castanea ), and Brewer's dwarf flax ( Hesperolinon breweri ). It is home to a variety of wildlife including deer, mountain lions, coyotes, foxes, bobcats, golden eagles, and a variety of hawks. The endangered San Joaquin kit fox ( Vulpes macrotis mutica ) and threatened California red-legged frog ( Rana draytonii ), California tiger salamander ( Ambystoma californiense ) and Alameda whipsnake ( Masticophis lateralis ) are present as well. The park

1425-623: The U.S. Board on Geographic Names rejected the petitions, saying there was no compelling reason to change the name. In 2009 Mijares again proposed the name Mount Reagan to the United States Board of Geographic Names because the late president was by then eligible. The board gave the Contra Costa County Supervisor's Committee until March 31 to file an opinion. Individual members of the committee have responded that although they respect Reagan, Mount Reagan

1500-540: The University of California, Berkeley . In 1944 she published her book, The Flowering Plants and Ferns of Mount Diablo, California . Her study boundaries became the basis for the state park's first map and for the park's eventual expansion. Her work also became the origin of many of the park's place names. Mount Diablo was used for broadcasting purposes in the 1950s by radio station KSBR-FM and television station KOVR (channel 13). The Mount Diablo site gave KOVR, which

1575-567: The city of Walnut Creek , and east to the Los Vaqueros Reservoir watershed. The new Marsh Creek State Park and Black Diamond Mines Regional Preserve are among the open spaces stretching to the north. In this way the open spaces controlled by cities, the East Bay Regional Park District, Mount Diablo State Park, and various regional preserves now adjoin and protect much of the elevated regions of

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1650-474: The movements of the Earth's plates . The mountain lies between converging earthquake faults and continues to grow slowly. While the principal faults in the region are of the strike-slip type, a significant thrust fault (with no surface trace) is found on the mountain's southwest flank. The uplift and subsequent weathering and erosion have exposed ancient oceanic Jurassic and Cretaceous age rocks that now form

1725-570: The "Black Diamond Railroad"), built in 1868. The railroad connected Nortonville with the San Joaquin River , at Black Diamond Landing, California, with a stop at Cornwall, California (the latter two towns are now a part of the city of Pittsburg, California ). The town was home to many Welsh miners. In 1885 the Black Diamond Coal Mining Company moved all the coal miners from Nortonville to another of

1800-482: The 1920s to the 1940s. The Hazel-Atlas mine is being restored and maintained by park staff and can be visited on guided tours which cover the area's mining history and geology. Inside the Greathouse portal, a 950 foot (290 m)-long section of the entrance corridor has been made into a museum. The first section is a series of self-guided exhibits, while the larger second section (which has a separate entrance from

1875-489: The Company's mines at Black Diamond , Washington Territory . The Nortonville mine was so deep that it acted as a drain for the surrounding mines, and when the owners of the other mines refused to contribute to the cost of pumping out the water, the company simply shut down and moved its operations. Currently what is left behind at Nortonville is a deserted area. The brick foundation of the mine's hoisting works, remnants of

1950-475: The Diablo Trail , the most accurate and up-to-date map of Mount Diablo's more than 90,000 acres (36,000 ha) of protected lands. It includes 100 access points, 520 miles (840 km) of trail, and 400 miles (640 km) of private fire roads. Mount Diablo is a geologic anomaly about 30 miles (50 km) east of San Francisco. The mountain is the result of geologic compression and uplift caused by

2025-805: The Mount Diablo Region, they were hunted to extinction by 1850. Northwards expansion of Diablo Range elk to Mount Diablo has been blocked by Interstate 580 . However, in 2006 a bull elk swam 4 miles (6.4 km) across Suisun Bay from the Grizzly Island herd to Contra Costa County, and historically large herds crossed the Carquinez Strait . Entrance stations are located at the end of Northgate Road (in Walnut Creek ) and Diablo Road (in Danville ). The Danville entrance

2100-733: The Preserve cross rolling foothill terrain covered with grassland, California oak woodland , California mixed evergreen forest , and chaparral . Long before the widespread ranching and mining activity that took place in the area, indigenous people had a presence in the Bay Area for 13,000 years. Three Bay Miwok tribes, the Chupcan , Ompin, and Volvon, lived in the areas surrounding the Black Diamond Mines Regional Preserve. The Chupcan occupied territory to

2175-483: The San Francisco Bay Area. Mount Diablo appears from many angles to be a double pyramid and has many subsidiary peaks. The largest and closest is North Peak, the other half of the double pyramid, which is nearly as high in elevation at 3,557 feet (1,084 m), and is about one mile (1.6 kilometers) northeast of the main summit. The mountain is within the boundaries of Mount Diablo State Park , which

2250-574: The Spanish mission system. Between 1804 and 1806, the majority of Volvon Bay Miwok were split up and baptized at either Mission Dolores or Mission San Jose . A Spanish military raid caused the Chupcans to flee to Suisun territory in 1804, and by 1811, most Chupcans were split up and baptized at either Mission Dolores or Mission San Jose . In 1810, some members of the Ompin went to Mission Dolores, and

2325-521: The area traditionally had a variety of creation narratives associated with the mountain. In one surviving narrative fragment, Mount Diablo and Reed's Peak ( Mount Tamalpais ) were surrounded by water; from these two islands the creator Coyote and his assistant Eagle-man made Native American people and the world. In another, Molok the Condor brought forth his grandson Wek-Wek the Falcon Hero, from within

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2400-518: The coal mines closed, the towns were abandoned and the area was used mainly for cattle grazing. In 1974 the Southport Land and Commercial Company (former Black Diamond Coal Mining Company) donated 160 acres of its land holdings to help It become Black Diamond Mines Regional Park. The coal mines are closed due to hazards posed by the age of the mines, the gases they produce (carbon dioxide and methane), and their rock quality (the shale and coal in

2475-479: The continental shelf began to rise up once again. In 1859 William C. Israel discovered a coal deposit while clearing out a spring on his land at Horse Haven Valley, six miles south of Antioch. His initial attempt to mine the coal was not financially successful but soon other coal deposits were discovered nearby and mining operations grew rapidly. The area became known as the Mount Diablo Coalfield,

2550-537: The dawn of time". Further inland, the Nisenan of the Sacramento Valley call it Sukkú Jaman , "dog mountain"; because, as Nisenan elder Dalbert Castro once explained, it's "the place where dogs came from in trade". A Southern Sierra Miwok name for the mountain is Supemenenu , and a Northern Sierra Miwok name is Oj·ompil·e . It has also been suggested that another early Native American name for

2625-427: The decades. Soon after Earth Day in 1971, the nonprofit organization "Save Mount Diablo" was created by co-founders Mary Bowerman and Art Bonwell, barely ahead of real estate developers. At the time, the state park included just 6,788 acres (2,747 ha) and was the only park in the vicinity of the mountain. In 2007 the state park totaled almost 20,000 acres (8,100 ha), and with 38 parks and preserves on and around

2700-509: The east. The sites of Judsonville and West Hartley are located on private property outside the eastern boundary of the Preserve. The mines were the Empire, Central, Star, Corcoran, Pittsburg, Manhattan, Eureka, Independent, Union, Black Diamond, Mt. Hope, and Cumberland. The coal produced was of a low grade (sub-bituminous or lignite), but for a time in the 19th century, was the only readily accessible and economic source in California. Therefore, it

2775-431: The image, "Poplars, Cemetery near Mount Diablo". The land the cemetery occupies was originally owned by the Black Diamond Coal Mining Company and was given to Contra Costa County by Emma Rose, the daughter of Black Diamond Mining Company president Alvinza Hayward. The original records for the cemetery were destroyed in the 1906 San Francisco earthquake and fire. Few people buried in the cemetery are identified. Many of

2850-421: The individual plots were never marked. More had only a wooden marker – nearly all of which were destroyed over the years by either wildfires that swept through the area or by insects, weather, or other natural cause. Vandals are said to have carried off some of the more permanent stone markers. A few whose earthly remains were laid to rest here include: In the 1920s, a mine producing high-quality silica sandstone

2925-596: The land to the Black Diamond Mines Regional Preserve. Grevelle estimated the market value of his donation at $ 3.5 million in 2016 (~$ 4.36 million in 2023). Mount Diablo Mount Diablo is a mountain of the Diablo Range , in Contra Costa County of the eastern San Francisco Bay Area in Northern California . It is south of Clayton and northeast of Danville . It is an isolated upthrust peak of 3,849 feet (1,173 meters), visible from most of

3000-470: The largest in California, producing more than 400 million short tons (357 million long tons) of coal during this time. The area includes the remains of twelve coal mines and the sites of several long-gone coal mining towns. The Preserve contains over 200 miles (320 km) of mine workings. The largest and oldest town, Nortonville , had a peak population of about 1,000. Somersville , Stewartville , West Hartley and Judsonville were located in valleys to

3075-477: The marshlands. These sediments, along with the favorable hot and humid climate, fueled the growth of coastal marsh flora that eventually formed into coal. Tectonic activity towards the end of this sedimentation cycle caused the continental shelf to sink and resulted in sediments being deposited into deeper water. The Mount Diablo Mountain Range of today was created at the beginning of the fourth depositional cycle when

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3150-507: The mines is unstable). In 1980 four young boys from the local area were killed by the methane gas from one of the open mines. However, a number of mine openings have been turned into public-access openings which allow visitors to look into the mines and, for some, to walk a short distance underground. The deepest public-access opening is known as Prospect Tunnel. Visitors can enter 200 feet (61 m) of this excavation made by miners searching for coal. Rose Hill Cemetery, officially designated as

3225-618: The mountain was Kawukum or Kahwookum , but there is no evidence to confirm the assertion. According to Indian historian Bev Ortiz and Save Mount Diablo: "The name Kahwookum was made up in 1866 — with no real Native American connection — referred to the California Legislature's Committee on Public Morals, and tabled. It resurfaced as a real estate gimmick in 1916 with a supposed new translation, "Laughing Mountain", attributed without documentation to Diablo area Volvon Indians. Most of Mount Diablo, including its peak,

3300-514: The mountain were created in 1874 by Joseph Seavey Hall and William Camron (sometimes "Cameron"); Hall's Mount Diablo Summit Road was officially opened on May 2, 1874. Camron's "Green Valley" road opened later. Hall also built the 16-room Mountain House Hotel near the junction of the two roads, a mile below the summit (2,500 foot elevation. (It operated through the 1880s, was abandoned in 1895, and burned c. 1901). As far north as Meridian Road, on

3375-862: The mountain were mined in the 19th and early 20th centuries, but are now open to visitors as the Black Diamond Mines Regional Preserve . Guided tours of the sand mines and coal field are provided. The park's vegetation is mixed oak woodland and savannah and open grassland with extensive areas of chaparral and a number of endemic plant species, such as the Mount Diablo manzanita ( Arctostaphylos auriculata ), Mount Diablo fairy-lantern ( Calochortus pulchellus ), chaparral bellflower ( Campanula exigua ), Mount Diablo bird's beak ( Cordylanthus nidularius ), Mount Diablo phacelia ( Phacelia phacelioides) and Mount Diablo sunflower ( Helianthella castanea ). The park includes substantial thickets, isolated examples, and mixed ground cover of western poison oak . (It

3450-498: The mountain's viewshed is the largest in the world‍—‌or second largest after Mount Kilimanjaro ‍—‌are ill-founded. It does boast one of the largest viewsheds in the Western United States and played a key role in California history. Mount Diablo is sacred to many California Native American peoples. According to Miwok mythology and Ohlone mythology , it was the point of creation. The local peoples of

3525-444: The mountain, Diablo's public lands total more than 90,000 acres (36,000 ha). According to Save Mount Diablo, there are 50 individual preserves on and around Mount Diablo, some of which are conservation easements covering a single parcel, others are expected to eventually be absorbed into larger nearby parks. As of December 2007, the organization recognizes 38 specific Diablo parks and preserves. The State Park adjoins park lands of

3600-515: The mountain. About 25 independent tribal groups with well-defined territories lived in the East Bay countryside surrounding the mountain at time of European contact. Their members spoke dialects of three distinct languages: Ohlone , Bay Miwok , and Northern Valley Yokuts . The Chochenyo -speaking Ohlone from Mission San Jose and the East Bay area, call the mountain Tuyshtak , meaning "at

3675-508: The mountain. There are unprotected areas in Arroyo del Cerro, Curry Canyon, the Marsh creek region, and on the northern slopes of North Peak, and in a number of inholdings surrounded by preserve land. Park expansion continues on all sides of the mountain although its western boundaries are largely complete. Extensive development continues in the southwestern foothills and Tassajara region, such as

3750-500: The mountain; a regular single track trail completes the loop. There are 520 miles (840 km) of hiking and equestrian trails, some available for mountain biking . Camping facilities are available within the park. There are numerous picnic sites. Pets are restricted and require proper documentation for rabies (not just a tag). Daytime visitors must exit the park by sunset except for special events. Some picnic spots may be reserved but most are available without reservation. Alcohol

3825-465: The northeast peak of Mount Diablo "Mount King", after Rev. Thomas Starr King , a Unitarian clergyman, abolitionist, Republican, Yosemite advocate, cultural Unionist, and California's leading intellectual. Today it is known simply as North Peak. In 2005 Arthur Mijares, from the neighboring town of Oakley , petitioned the federal government to change the name of the mountain, claiming it offended his Christian beliefs. Additionally, he claimed that Diablo

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3900-471: The northern extreme of the range of Coulter pine ( Pinus coulteri ). This species may be seen along the Coulter Pine Trail near the north (Mitchell Canyon) entrance. In 2005 the endangered species Mount Diablo buckwheat ( Eriogonum truncatum ), thought to be extinct since last seen in 1936, was rediscovered in a remote area of the mountain. All vegetation, minerals and wildlife within

3975-472: The open (as on trails and ledges) on cool, sunny days. Other wildlife to avoid include fleas, ticks and mosquitoes. There has also been an increase in the mountain lion or puma ( Puma concolor ) population in the larger region and one should know how to respond if these animals are encountered. Please see the mountain lion safety tips in the mountain lion article. Although tule elk , an elk subspecies found only in California, were historically native to

4050-549: The outside), houses a reconstruction of the Hazel-Atlas works as it would have appeared around 1940. EBRPD originally repurposed the Hazel-Atlas mine as a museum in the 1970s, but storm damage in 2007 forced closure of this attraction for extensive repairs. It did not reopen for five years. The trails offer views of Mount Diablo , the Sacramento-San Joaquin River Delta , and on clear days,

4125-493: The outskirts of Chico, California , the summit was used as a reference point. The road is colinear with the summit, and is named for the meridian which intersects it. An aerial navigation beacon, the Standard Diablo tower, was erected by Standard Oil at the summit in 1928. The 10-million-candlepower beacon became known as the "Eye of Diablo" and was visible for a hundred miles. After initial legislation in 1921,

4200-426: The park are protected and it is illegal to remove such items or to harass any wildlife. Commonly seen animals include coyote , bobcat , black-tailed deer , California ground squirrels , fox squirrels and grey foxes ; many other mammals including mountain lions are present. It is a chief remaining refuge for the threatened Alameda whipsnake , California red-legged frog . Less common wildlife species include

4275-438: The popular Falls Trail, which features several seasonal waterfalls. Nortonville, California Nortonville is an unincorporated ghost town in Contra Costa County, California . It was located on Kirker Creek 5.5 miles (9 km) north-northeast of Mount Diablo , at an elevation of 801 feet (244 m). Nortonville is located on Nortonville Road just outside the city of Pittsburg in Contra Costa County . The town site

4350-571: The railroad bed, and an old cemetery are all that remain. The cemetery is known as the "Rose Hill Cemetery," which was named for Emma Rose, daughter of Alvinza Hayward , who was president and chief stockholder of the Black Diamond Coal Mining Company. In the 1940s Mrs. Rose donated the cemetery to the county. Four other coal mining towns were established in the same mining district: Somersville , Stewartsville , West Hartley and Judsonville . A post office operated at Nortonville from 1874 to 1910, with closures in 1887 and from 1890 to 1891. Here

4425-498: The region north of the mountain came to be known as Monte del Diablo ("devil's thicket"; in this case monte should be translated as thicket or dense woods). It was shown on maps near present-day Concord (formerly known as Pacheco ). Later, U.S. settlers understood "Monte" to refer directly to the mountain, and it was recorded with varying degrees of certainty until "Mount Diablo" became official in 1850. In May 1862, California Geological Survey field director William H. Brewer named

4500-414: The reintroduced peregrine falcon , ringtail cats , and to the east American badgers , San Joaquin kit fox , roadrunners , California tiger salamander , and burrowing owls . There are also exotic (non-native) animals such as the red fox and opossum , the latter being North America's only marsupial . In September and October male tarantula spiders can be seen ( Aphonopelma iodius ) as they seek

4575-715: The remaining members went to Mission San Jose in the years 1811 and 1812. The rich coal deposits and sandstone hills of Black Diamond Mines Regional Preserve were formed by geological activity in the Tertiary period . In the period between the Paleocene epoch and Miocene epoch of the Tertiary era, the North American Plate and the Pacific plate came together at a subduction zone where the North American Plate

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4650-596: The state are taller, but Mount Diablo has a remarkable visual prominence for a mountain of such low elevation. Its looming presence over much of the Bay Area , delta , and Central Valley , and good visibility even from the Mother Lode , all key regions during the gold rush and early statehood , made it an important landmark for mapping and navigation. The summit is used as the reference datum for land surveying in much of northern California and Nevada. Claims that

4725-605: The state of California acquired enough land in 1931 to create a small state park around the peak. Many improvements were carried out in the 1930s by the Civilian Conservation Corps , but park expansion slowed in the 1940s through the 1960s. Significantly, botanist Mary Leolin Bowerman (1908–2005), founder of the Save Mount Diablo non-profit in 1971, published her Ph.D. dissertation in 1936 at

4800-618: The summit. The mountain grows from three to five millimeters each year. The upper portion of the mountain is made up of volcanic and sedimentary deposits of what once was one or more island arcs of the Farallon Plate dating back to the Jurassic and Cretaceous periods, between 90 and 190 million years ago. During this time, the Farallon Plate was subducting beneath the North American continent. These deposits were scraped off

4875-616: The top and accreted onto the North American Plate . This resulted in the highly distorted and fractured basalt and serpentine of the Mount Diablo Ophiolite and metasediments of the Franciscan Complex around the summit. East of the subduction zone, a basin was filling with sediment from the ancestral Sierra further to the east. Up to 60,000 feet (18,000 m) of sandstone, mudstone, and limestone of

4950-847: The upscale development of Blackhawk and individual estates overlooking the Livermore Valley on Morgan Territory Road. Other large projects are proposed in the northern Black Diamond Mines and Los Medanos foothills, at the Concord Naval Weapons Station, and near Marsh Creek State Park. Large-scale development of other private parcels is restricted by city and county urban limit lines, by lack of water, excessive slope, and sensitive resources including rare species. Development of smaller ranchette subdivisions continue to fragment and threaten many parcels and large areas of habitat. In 2007 Save Mount Diablo published Mount Diablo, Los Vaqueros & Surrounding Parks, Featuring

5025-444: The various formations into their current juxtaposition. This faulting action continues to change the shape of Mount Diablo, along with the rest of the Coast Ranges. The summit area of Mount Diablo is made up of deposits of gray sandstone , graywacke , chert , oceanic volcanic basalts (greenstone) and a minor amount of shale . The hard red Franciscan chert is sedimentary in origin and rich in microscopic radiolaria fossils . In

5100-474: The west of the preserve near Concord , the Volvon occupied the territory to the south including much of Mount Diablo , and the Ompin occupied the area to the north including Pittsburg , Collinsville , and the intervening waterway. Black Diamond Mines Regional Preserve is located in a boundary area between these three tribes. At the beginning of the 19th century, these three tribes were significantly impacted by

5175-428: The western foothills of the mountain there are large deposits of younger sandstone rocks also rich in seashells, severely tilted and in places forming dramatic ridgelines. Mount Diablo forms a double pyramid which gives the appearance of a volcano although in fact it is formed of ancient sea floor rock being uplifted by relatively recent tectonic forces. Deposits of glassmaking-grade sand and lower-quality coal north of

5250-548: Was a very valuable resource and powering the railroads, ships and heavy industry of California. The mineral was often called 'black diamond." The coal was carried to the San Joaquin River by three railroads: the Empire, Pittsburg, and Black Diamond , for shipment by barge to markets in San Francisco , Sacramento , Stockton and other communities. Coal mining activity ended as better-quality imported coal became affordable and as petroleum emerged as an energy source. After

5325-524: Was based in Stockton , regional coverage that also included San Francisco and Sacramento . However, it also forced the station to pay San Francisco rates for movies and impeded any attempt at obtaining network affiliation. In 1957, the station relocated to Butte Mountain in Jackson in order to become an ABC affiliate and remove its signal from the Bay Area. This state park has been greatly expanded over

5400-474: Was formed during the third marine sediment deposition cycle which took place during the middle of the Eocene epoch . At the beginning of this third cycle, tectonic activity caused an uplift of the continental shelf seafloor, resulting in the creation of shallow marshes. Erosion during this era brought an abundance of sediment into the shallow sea covering the continental shelf, with some sediment making its way into

5475-613: Was pushed over the Pacific Plate. During this era, the Pacific Ocean stretched over much of the California central valley with the coastline reaching the lower regions of the Sierra Nevada mountains. Tectonic activity between the North American and Pacific plate, along with sea level changes, brought about four series of marine sediment deposition. The coal that was mined from the Mount Diablo Coal Field

5550-834: Was started by owner Marvin Greathouse on a hillside above the Somersville townsite. He sold the product to the Hazel-Atlas Glass Company which operated a plant in Oakland manufacturing glass containers. Hazel-Atlas eventually purchased the mine and operated it until about 1945. Another sandstone mine in the Nortonville area produced sand used by the Columbia Steel mill in Pittsburg, California for steel casting. The two companies recovered more than 1.8 × 10 short tons (1.6 × 10 long tons) of sand between from

5625-444: Was within the homeland of the early Volvon (sometimes spelled Wolwon, Bolbon or Bolgon), a Bay Miwok –speaking tribe. As early as 1811, Spanish colonists referred to the mountain as Cerro Alto de los Bolbones ("High Hill of the Volvon") or sometimes Sierra de los Bolgones . The conventional view is that the peak derives its name from the reaction of Spanish soldiers to the 1805 escape of several Chupcan Native Americans in

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