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A History of Mt Diablo
Prepared by Seth Adams, Director of Land Programs, Save Mount Diablo
Reprinted from Mount Diablo Review, Fall 2000
History of Mount Diablo

Geologic Summary: 165 million B.C.

Mount Diablo began as volcanic rock beneath the surface of the Pacific

Ocean was scraped into a mass between the Pacific tectonic plate and

the overlying sedimentary layers of the North American plate. As ice

ages affected sea levels, sedimentation continued in shallow coastal

seas. About four million years ago, the older, harder volcanic material

from the sea floor forced its way up from between the two plates

heaving the weaker sedimentary layers up an angle. Over time,

younger rock above eroded and by 2 million B.C. the older rock we

recognize as Diablo's peaks was exposed as low-lying hills.


Human History: ca. 2000 B.C.

According to one tradition, at the Dawn of Time, Mount Diablo and

Reed's Peak were surrounded by water. From these two islands the

creator Coyote and his assistant Eagle-man made Indian people and

the world. In a Plains Miwok creation account, Mol-luk (Condor man)

lived on the north side of Mt Diablo. His wife, the rock on which he roosted, gave birth to Wek-wek (Prairie Falcon-man). With the help of his grandfather Coyote-man, Wek-wek created Indian people, providing them with "everything, everywhere so they can live".

March, 1772 Fages-Crespi expedition.

Lt. Pedro Fages and Father Juan Crespi explored the Carquinez Straits and the western side of the mountain into the San Ramon Valley. In 1782 they returned to the mountain, climbing to the summit.


4-1/3, 1776 de Anza-Font expedition. Juan Bautista de Anza and Father Pedro Font conducted a second expedition circling the northern part of Diablo from Pacheco to present-day areas of Concord, Antioch and Byron. The de Anza expedition included Juan Salvio Pacheco whose grandson, Salvio Pacheco, founded Concord.

1800 Spaniards begin using Mount Diablo for winter grazing

after the Mission San Jose was founded in 1797 (in part to more easily missionize East Bay natives). In 1819 from the mountain's slopes Lt. Jose Maria Estudillo wrote "The view from south to north is beautiful, for its end cannot be seen".


Ca. 1805-1806 The naming of Mount Diablo.

General Mariano G Vallejo, in an 1850 report to the Legislature, gives the derivation of the name of Mount Diablo from its Native American to Spanish to Anglo form. In 1806 Spanish soldiers were pursuing native Americans as part of the missionization, the natives took cover in a thicket near Pacheco and the Spaniards camped with the intention of rounding them up in the morning. During the night the natives escaped across the Carquinez Strait, an act only possible, according to the Spaniards, with the help of the Devil ("Diablo"). The thicket became known as "Monte del Diablo" and Anglo settlers later misunderstood that the word "monte" can mean "thicket" or "mountain", and fastened the name on the most obvious local landmark.


1822 & 1824 Spain ceded California to Mexico, the Mexican Revolution took place and the beginning of land grants, including 18 in what became Contra Costa County. Between 1833 and 1846 three Rancho San Ramon Mexican land grants established to Bartolome Pacheco (southern San Ramon Valley) and Mariano Castro (northern San Ramon Valley, two square leagues), and Jose Maria Amador (four leagues).


7-31-1834 Ranch Arroya de las Nueces y Bolbones or 'Rancho Miguel'

17,782 acres were granted to Don Juana Sanchez de Pacheco including Pine Canyon, Little Pine Canyon and the North Gate Road area, Diablo and Turtle Rock Ranches. Approximately ¼ of the land grant is within the State Park today.

1837 Dr John Marsh, "Brentwood".

Dr John Marsh, Contra Costa's first American settler, acquired Rancho Los Meganos from Jose Noriega of San Jose, approximately 13,285 acres for $500. c. 1835, Marsh's stone mansion (John Marsh Home) built at his rancho; the home is named "Brentwood' for his ancestral lands in England. Marsh was killed before the home was completed.


1841 The first travel account of Mount Diablo

Eugene Duflot du Mofras – French attaché to California. By 1846 American immigration to the area had begun.


1848 Coal reported in CCC and on 1-24-1848 Gold was discovered at the American River,

leading to rapid population increase in California.


1848 Treaty of Guadalupe Hidalgo.

Alta California becomes American territory, and much of Mount Diablo, sobrante lands bounded by Spanish land grant ranchos, was designated public domain and for homesteading at a minimum price of $1 per acre. In 1849 Frances E. Matteson came to California and homesteaded 160 acres which later became part of the Blackhawk Ranch. He hunted deer, bear, elk and antelope.


Ca. 1850 Morgan Territory.

Jeremiah Morgan moved form the Ygnacio Valley to unsurveyed public land on the east side of Mount Diablo, ca. 1850, because the grizzly bear hunting was so good. Francis Such and W. E. Whiting discover lime on the northwest foothills of Mount Diablo on what becomes known as "Lime Ridge".


4-1850 Naming of Mount Diablo.

General Mariano Guadalupe Vallejo, in a Constitutional Convention report to the State Legislature, discussed the naming of Mount Diablo. "It was intended to call the county (Mount Diablo), but both branches of the Legislature, after warm debates on the subject, resolved upon the less-profane one (name) of Contra Costa. (Including present-day Alameda County). (Also see article on name change request and denial)


1851 Mount Diablo meridian and survey. 

Colonel Leander Ransom, Deputy-Surveyor General, established the initial point of the Mount Diablo meridian at the mountain's summit, beginning the survey of public lands in California. The hills north of the Clayton area became known as the meridian Hills (the ridge between Concord and Pittsburg).


1852 The US Coast and Geodetic Survey used Mount Diablo as a base point for its National Triangulation Survey. Walnut Creek's population is less than 50. On 5-18-1852 Alamo (Spanish for "poplar" or "cottonwood") is designated and a post office established on the northern Rancho San Ramon.


1857 Joel Clayton, an English immigrant, founded Clayton.

In 1859 coal is discovered north of Clayton. For a time it is the chief source of fuel for manufacturing on the west coast. The two towns of Somersville and Nortonville ultimately included about 1,000 residents each and became ghost towns around 1885.



"Almost every Californian has seen Monte Diablo. It is the great central landmark of the state. Whether we are walking in the streets of San Francisco, or sailing on any of our bays and navigable rivers, or riding on any of the roads in the Sacramento and San Joaquin Valleys, or standing on the elevated ridges of the mining districts before us – in lonely boldness, and almost every turn, we see Monte Diablo". J.M. Hutchings, from Scenes of Wonder and Curiosity in California.


Bret Harte and the Legend of Monte del Diablo.

Farmer Abner Bryant hired a tutor for his sons on his Sycamore Valley farm (on the present-day Blackhawk Ranch), the first job for future-writer Francis Bret Harte (lived 1836-1902). Harte later wrote the most widely-reported myth regarding the naming of Mount Diablo, "The Legend of Monte del Diablo".


1861 Whitney's California Geological Survey visits Mount Diablo.

William Brewer wrote "The region north and northwest of Mount Diablo is a beautiful one – pretty valleys scattered over with oaks, many of enormous size, with wide branches, often dropping like the elm. The rugged mountain rises against the clear sky, and when illuminated by the setting sun is an object of peculiar beauty. Our camp was in a very pretty place, with great trees around, and the mountain in full view." The Survey gathered rocks, fossils and plants (including 25 plants not then known and measured the mountain's elevation at 3,890 ft.


4-30-1862 Description of View, Mount Diablo elevation.

Brewer estimated that the view embraced 80,000 square miles, 40,000 "in tolerably plain view – over 300 miles from north to south, and 260 to 280 miles from east to west". The view includes 60% of California, 35 counties and an area equal to the six New England states. Brewer's party calculated the height of Mount Diablo at 3,876.4' (actual 3,849').


1863 Major drought

throughout California, many county residents survived by working at the lime quarries. Copper ores with traces of gold were found in Mitchell and Bagley Canyons, at Eagle Peak, and there was a short-lived copper and gold rush. In 1863-4 L.W. Hastings discovered quicksilver (mercury) on the northeast side of North Peak and Perkins Canyon was mined until the 1950's.

1865-66 Legislative attempt to change the name of Mount Diablo.

The State Legislature made an unsuccessful attempt to change the name of Mount Diablo to "Coal Hill'. Clayton resisted the name change.


1870's The Green and Sycamore Valleys

are well-populated, most of the southern area is used for thoroughbred horses (until WW1), as was Perkins Canyon. In 1873 William Cameron began buying land in Green Valley. Several railroads also began purchasing land, and in time a single owner of the "Big Four" emerged, Central Pacific Railroad, which appointed David Colton (died 1878) to manage the 10,000-acre "Railroad Ranch". He was given Mark Hopkins share, and in time bought out Crocker, Huntington and Stanford.


First Wagon Road up Mount Diablo and the Mountain House Hotel constructed.

Green Valley and "Mount Diablo Summit Road Company" incorporated to build the first toll wagon roads up the mountain, by local investors including Cameron and Joseph Hall, who also built the 16-room Mountain House Hotel a mile below the summit (operated through the 1880's, abandoned 1895, burned c. 1901). In 1874 Seeley J Bennett inaugurated a stage line from Martinez to the Diablo peak, by 1879 including hundreds of visitors a year. Kate Nevins, who had worked at the Mountain House wrote "Citizens from all over the state made pilgrimage with wagon loads, journeying to the Mountain House then hiking to the observatory at the top. They stayed sometimes for weeks to enjoy Pine Canyon, one of the finest beauty spots on earth with its magnificent views of the Castle Rocks."

1876 The US Coast and Geodetic Survey erected a three-story signal station at the Summit,

which was later equipped with a telescope by Joseph hall for the use of Mountain House guests (it burned 7-4-1891 when fire swept up from Morgan Territory). Hall also had a floored tent at the summit for guests who wished to sleep there.


1877 Cook Farms, Oakwood Park Stock Farms.

Colton's daughter Caroline and her husband, mining engineer Dan Cook, inherited the Railroad Ranch, which by then extended from Green Valley School to Sycamore Valley and to Curry Creek, taking in the headwaters of Marsh Creek, the southern summit road and the Mountain House Hotel. Brothers Dan and Seth Cook (both 'rough, obscenity-speaking and hearty fellows' according to R.N. Burgess) and changed the name to Cook Farms. Seth, a bachelor, inherited and passed the farm to his niece Louise and her husband John F. Boyd. Boyd renamed it the Oakwood Park Stock Farms and by 1897 it included 6,000 acres. By 1913 it grew to 15,000 acres, including areas of Dan Cook Canyon, Rock City, Devil's Slide and the area along South Gate Road, and was considered the largest stock farm in the world.


1879 Concord had a population of 300 and in 1880 the village of Walnut Creek included about 300 people.

Over the next decade major fired scarred Mount Diablo, reportedly started by careless hikers and campers, leading to landowner calls to close the mountain to the public.


1890 John Muir, one of the founders of the American Conservation Movement, moved to Martinez,

until his death in 1914. By the 1890's grizzly bear and great herds of elk had disappeared from the area. Sunday picnics were often held at Mitchell or Pine Canyon. William Cameron died and his daughter Kate McLaughlin Dillon sold off her father's holdings, including White Canyon and Deer Flat to Dominic Murchio, an Italian immigrant with a ranch alongside Mitchell Creek, including part of Mount Zion. "Clear and cool. Beautiful silvery haze on Mount Diablo this morning, on it and over it – outlines melting, wonderfully luminous." - John Muir, 1895.


1899 Borges Ranch established at Shell Ridge.

Frank Borges buys 700 acres (now preserved within Shell Ridge Open Space). Designated on the National Register of Historic Places in 1981.


1900's Contra Costa included 18,000 citizens at the turn of the century,

645 in Concord. The County includes 900,000 today. During the county's first decade, President Theodore Roosevelt ushers in a first wave of American Conservation.


1903 First tunnel

through the Oakland Hills (now Old Tunnel Road). The tunnel inaugurates waves of new residents. In 1904 public electricity is established locally and in 1907 the first automobile garage.


1907 The Henry Cowell Lime and Cement Company moved to the Diablo Valley at Lime Ridge

and built the town of Cowell, employed 250 men, ran 24 hours a day (part of the area is now preserved in Lime Ridge Open Space).


1911 First electric train extended into the County,

the Oakland, Antioch and Eastern Railway through a 3,400 ft tunnel in the Oakland Hills to Walnut Creek to carry lime. Special trains ran for the R.N. Burgess Co., which sold land adjacent to the mountain at Diablo (June 2, 1914-1924).


1912 The Mount Diablo Development Co. established.

Louise Boyd sold Oakwood Park Stock Farm to R.N. Burgess and his Mount Diablo Development Co., a group of investors who wanted to create an exclusive residential park. They remodeled Cook's Clubhouse/Casino as the Mount Diablo Country Club and opened Mount Diablo to the public. Burgess then acquired the area later known as Blackhawk Ranch and all the land between it and Diablo, up to the summit, including the right-of-way to Mount Diablo Scenic Boulevard.


1912-15 Mount Diablo Auto Toll Road.

Burgess' group built new toll roads accessible to auto traffic all the way to Diablo's summit (North Gate and Mount Diablo Scenic Blvd – completed 1915).


1916 Castle Hotel planned for Mount Diablo Summit.

Mount Diablo Development Co. planned a tower-hotel "Torre de Sol" (never built) with promised investment and national publicity by William Randolph Hearst. World War 1 intervened, Hearst's interest waned, Burgess' company went bankrupt and of the planned development only the community of Diablo was ever built.


1917 Blackhawk Ranch founded.

Ansel Mills Easton (the uncle of the photographer Ansel Adams) and his son-in-law William A. Ward purchased 1200 acres from R.N. Burgess and started the Blackhawk Ranch named for a famous Irish race horse "Black Hawk" he had owned. Meanwhile, Portuguese immigrant Frank Macedo purchased 825 acres in what is now a park staging area in Alamo.


1921 Mount Diablo State Park created.

Mount Diablo was one of the seven state parks created before the establishment of the California State Park System in 1927, a "state park and game refuge" on 630 acres (from Burgess' Mount Diablo Development Co.,) administered by its own appointive Mount Diablo State Park Commission.

1927-28 California Park Survey.

Frederick Law Olmstead prepared a statewide survey (the Olmstead Plan) for the newly-created State Park Commission, recommending acquisition of 5-6,000 acres at Mount Diablo to "amplify" and "round out" the small state park at the summit. Major properties were acquired along the historic Scenic Boulevard (South Gate Road), the North Gate Road and near the summit.


1928 Standard Diablo Tower.

Standard Oil of California constructed a 75 ft aviation beacon jointly with the U.S. Dept of Commerce to encourage and as a guide for commercial aviation (visible for 100 miles, first lit by Charles Lindberg). The beacon was later transferred to the Summit Building and is now lit only on 12-7 Pearl Harbor Day.


1929 Mary L. Bowerman, founder of Save Mount Diablo.

A young student at the University of California and future co-founder of Save Mount Diablo in 1971, Bowerman begins research on the botany of Mount Diablo, culminating in a 1936 Ph.D. thesis and the 1944 publication of the recognized work on Mount Diablo "The Flowering Plants and Ferns of Mount Diablo, California". Dr Bowerman continues as an active member of the Board of Directors of Save Mount Diablo in 2000.

1930's CCC Era on Mount Diablo.

The Great Depression and increasing calls for the municipalization of basic services ushers in the second wave of U.S. conservation, as public watersheds and parks are created. The Civilian Conservation Corps constructed Camp Diablo on the Danville side of Mount Diablo and built facilities at the mountain (among the best in the State's parks), realigning park roads, building hiking and fire trails, residences, picnic areas and campgrounds, dams and the Summit Building (1939-42).

1930 Proposal for the East Bay Regional Park District.

Publication of the Olmsted-Hall Report "Proposed Park Reservations for East Bay Cities" supported a Committee of East Bay Citizens proposal to create the East Bay Regional Park District from surplus East Bay Municipal Utilities District land, recommending a 10-11,000 acre park system extending 22 miles along the East Bay hills above the nine Bay shoreline cities below.


4-20-1931 Mount Diablo designated a unit of the new State Park System.

1934 Establishment of the East Bay Regional Park District.

In 1936 the S.F. to Oakland Bay Bridge is completed, and in 1937 the two-bore Caldecott Tunnel, making the East Bay and Central County much more accessible – the County's first major subdivision is approved that same year. Nobel Prize Winner Eugene O'Neill moves to Danville – "Mount Diablo, a mass of purple in the morning. Nature is always lovely, invincible, glad whatever is done or suffered by her creatures. All scars she heals; whether in rocks or waters or sky or heart."


1940's Population growth.

The 1940's census reports 1,587 people in Walnut Creek, 1,373 in Concord. Camp Parks' Seabees (Navy construction battalions) established Camp Diablo, a base at Rock City to train in mountain warfare, road and bridge construction. At the end of the war development booms.

1960's Population growth in the Sixties.

Contra Costa County population: 409,030, up 330,000 since 1930. Concord included 36,208 up from 1,373 in 1940. In 1966 much of Pine Canyon is added to the State Park.

1970's The Seventies – Environmental awareness and the first Earth Day usher in a new wave of conservation.

Concord becomes the County's largest city. Traffic increases dramatically, General Plan process instituted as state law, the California Environmental Quality Act and the federal and state Endangered Species Acts. A proposal to develop Shell Ridge is defeated and local bond issues are passed to acquire open space in Walnut Creek and Concord.

12-7-1971 Save Mount Diablo founded.

Co-founded by Art Bonwell and Dr Mary Bowerman. SMD was created because subdivisions were spreading toward the mountain, and no organization was working primarily on the area. Bowerman provided the organization's vision, while Bonwell was the nuts and bolts guy. Bowerman wrote "My dream is that the whole of Mount Diablo, including its foothills, will remain open space . . . that the visual and natural integrity will be sustained." In 1971 Contra Loma Regional Park was created.

1972 BART reaches interior Contra Costa County,

adding to growth pressures; working with the State, Save Mount Diablo helps preserve the mountain's northern canyons (Mitchell, Back, Donner) over the next several years. In 1973 Black Diamond Mines Regional Preserve and the City of Walnut Creek's Shell Ridge Open Space are created.

1-1974 Mount Diablo Interpretive Association founded

to work with the State Park in producing interpretive programs and publications.


1974 Blackhawk Development proposed.

Ken Behring acquired 4,200 acres of the Ranch and proposed subdivision. Save Mount Diablo negotiated for 2,052 acres to be dedicated to MDSP as a condition of develoment, including much of the Blackhills – the Wall Point area, Blackhawk Ridge, parts of Dan Cook and Jackass Canyons, and the area below Oyster Point, the single largest donation ever to a State Park.


1975 Morgan Territory Regional Preserve is created.

Concord population increases to 85,423 residents, up from 74,958 in 1966, 36,208 in 1960 and 1,373 in 1940.

1976 Save Mount Diablo's first acquisition

with private funds, the Morgan Territory Investment parcel at the corner of Marsh Creek and Morgan Territory Roads, Lime Ridge Open Space is acquired and Diablo Foothills Park is created at Pine Canyon. In 1977 a large fire burns from Clayton to Blackhawk In 1978 Mount Olympia and the Mount Diablo waterfalls are acquired.

1980's The Eighties, growth booms.

101,844 in Concord, up from 85,423 in 1975. North Peak and Prospector's Gap are added to the State Park in 1980 along with Long Ridge and Pine Canyon, Emmons Canyon in 1982, White Canyon and Black Point in 1984. In 1988 Save Mount Diablo hires its first staff. In 1989 Save Mount Diablo's Morgan Ranch acquisition connects the State Park with Morgan Territory Regional Preserve.

1988 Round Valley Regional Preserve is created

and in 1989 acquisition of the Los Vaqueros watershed and the Vasco Caves Regional Preserve begins.

1990 Senator Daniel Boatwright

"Someday when Contra Costa is 4 million people maybe someone will say 'I don't know who did this but thank God for whoever saved this in the past. You won't be here. I won't be here. But the legacy we leave should not simply be that we passed everything over."

1996 Acquisition of Brushy Peak Regional Preserve begins.


1999 SMD's 427-acre Silva Ranch acquisition

largely completes protection of Riggs Canyon.

9-25-1999 Mitchell Canyon Interpretive Center

opened by Mount Diablo Interpretive Association working with MDSP.


Informational sources: DPR, Edna May Andrews "History of Concord", Mary L. Bowerman "The Flowering Plants and Ferns of Mount Diablo, California", William H. Brewer "Up and Down California in 1860-1864", George Emanuel "Walnut Creek Arroya De Las Nueces", Virgie V. Jones "Historical Persons and Places… in San Ramon Valley", Bev Ortiz "Mount Diablo as Myth and reality; an Indian History Convoluted", George A. Pettit "Clayton; Not Quite Shangri-La", Nilda Rego "Days Gone by in Contra Costa County, California, Volume 1 & 2", W.A. Slocum & Co. "History of Contra Costa County, California", James C Stone "Diablo Legacy; Recollections & Reflections 1912-Present".

Summit Visitor Center | Clayton Worsdell

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