Boisduval's Blue Icaricia icariodes Lycaenidae Blues, Coppers, Hairstreaks Flies March to July Host Plant Lupine Nectar Plant Michael Marchiano Male Daniel Fitzgerald Underwing Ken-ichi Ueda Female

Geology FAQ Mount Diablo Geology Frequently Asked Questions Is Mount Diablo a volcano? No. Although basaltic lava rock can be found on the mountain, the lava was formed far at sea, upwelling from deep in the earth through fissures in the ocean crust. How high is the mountain? 3,849 feet. The summit is actually inside the museum. What kind of rock makes up the summit? The hard resistant rock on the summit is mostly greenstone (a slightly altered form of basalt, a common igneous rock that makes up much of the upper part of the ocean crust) and hard reddish chert with minor amounts of graywacke sandstone and shale. The exposed rock that you can stand on inside the summit museum is greenstone. Why does it stand up higher than the surrounding area? The rocks have been folded and lifted by compressional stresses in the earth’s crust. The greenstone and chert on the two main peaks are very resistant to erosion compared to many of the rocks in the surrounding areas and thus stand higher. Is Mt. Diablo still rising? The stresses that folded and raised the mountain are still at work and the mountain continues to slowly rise (about 0.1 inch a year) while the forces of weathering and erosion try to keep pace. How old is the mountain? The oldest rocks on the mountain are the greenstones in the mountain’s core formed about 190 million years old. But as a topographic feature, the mountain is relatively young, forming only during the past one million years or so. Is there any gold or silver here? Minor amounts of gold and silver associated with small copper deposits on the north side of the mountain were prospected, but production was not economical. Are the mercury mines still in operation? No. Mining operations stopped in the early 1970s after approximately $1,500,000 worth of mercury had been extracted. What are they quarrying on the north side? Diabase. Diabase is a dark igneous rock of fine crystalline texture. It is used primarily for building stones and crushed rock for roadbeds. Are there dinosaur bones in any of the rocks? Did they live here? No to both. The Mount Diablo region was under the ocean during the Jurassic and Cretaceous. The closest dinosaur bones to us were found near Pacheco Pass in central California. What about the bones at the Blackhawk Quarry? The quarry on the south side of the mountain is one of the richest mammal bone beds in the United States, second only to La Brea in Los Angeles. Bones from 9 million-year-old horses, camels, rhinos, and mastodons have been found here—but these are much younger than dinosaurs, which died out over 60 million years ago. The bones (only fragments are found, no complete skeletons) were preserved in stream deposits. How old are the fossils in the building blocks of the Summit Building? The clams, oysters, and other fossil shells in the building stones of the summit building came from the “Briones Formation” of Miocene age near Fossil Ridge and are about 12 million years old. How are the caves formed at Rock City? Although often called Wind Caves, they are only indirectly due to the wind. During the rainy season, water seeps into the rocks. The water is a very weak acid and slowly dissolves the cement that had been holding the sand grains together. The hot dry days of summer would draw the water to the surface of the rock where it evaporated and left behind the cement it had dissolved from deeper in the rock. After centuries of wet winters and dry summers, the inside of the rock had only a little cement, while the outside had a hard crust of sand grains tightly cemented. As wind and rain continued to beat on the faces of the rocks, holes developed in the crust. This exposed the loosely cemented grains underneath, which erode much faster than the surface, so that holes enlarged into little caves behind the hard crust. Very little of the hard crust remains on the surface of these rocks today. This text was reproduced from "Geology of Mount Diablo - A Training Manual" by Roi Peers

Privacy Policy of Mount Diablo Interpretive Association Mount Diablo Interpretive Association (MDIA) operates the https://mdia.org website (“the website”), which provides the public with information and resources on our organization’s mission and work related to the preservation and education of Mount Diablo State Park. This page is used to inform website visitors regarding our policies regarding the collection, use, and disclosure of Personal Information if anyone decides to use our Service, the Mount Diablo Interpretive Association website. If you choose to use our Service, then you agree to the collection and use of information with this policy. The Personal Information that we collect is used for providing and improving the Service. We will not use or share your information with anyone except as described in this Privacy Policy. 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2 Easy 4 miles Mitchell Canyon Nature Trail DESCRIPTION: This route follows Mitchell Creek and is extremely popular in the spring and early summer when wildflowers are abundant. There are ten identified stops following the Mitchell Canyon Trail Guide that can be obtained at the Mitchell Canyon Visitor Center. The route begins within an oak savanna woodland and then enters a riparian community. The shaded north exposures are alive with wildflowers in the spring. Watch for the California quail and butterflies as well. You may alter a portion of your return by following the Globe Lily Trail, which parallels Mitchell Canyon Road to the west between Red Road and Black Point Trail, and offers a modest elevation gain and provides wider vistas. DISTANCE DIFFICULTY See map, below TRAILHEAD KEY 3 TRAILHEAD: Mitchell Canyon TRAIL STATISTICS: This walk follows the Mitchell Canyon - Back Creek Loop (above) for the first two miles where the trail begins climbing by switchback up to Deer Flat. At the point where the climb begins, turn and retrace your walk. About 4-mile hike with a 500-foot elevation gain RATING: Easy

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. 1860 "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 Find more information below: History Mount Diablo Name Origin Contra Costa County Name Origin Blackhawk and the Mountain Mountain House Hotel Uncommon Place Names The Green Ranch Exploring History of Mount Diablo Scenic Road History Summit Building Mount Diablo Initial Point Communication Tower Blown Over Mitchell Canyon Visitor Center Opens John Muir Slept Nearby Cultural Heritage Early Inhabitants Cultural Heritage of Mount Diablo The Miwok Park History Park Opens 1931 Ranching Barbed Wire Bonanza

The Mount Diablo Observatory Association (MDOA) is dedicated to public education in astronomy. The organization includes scientists, engineers, and other professionals with a common interest in astronomy and a desire to further science education. MAILING ADDRESS: Mt. Diablo Observatory Association, Inc. P.O. Box 3165 Walnut Creek, CA 94598-3165 3 cups Blueberries 3 cups Flour 1½ cups Butter The Mount Diablo Observatory Association (MDOA) is dedicated to public education in astronomy. The organization includes scientists, engineers, and other professionals with a common interest in astronomy and a desire to further science education. MAILING ADDRESS: Mt. Diablo Observatory Association, Inc. P.O. Box 3165 Walnut Creek, CA 94598-3165 In celebration of the International Year of Astronomy 2009, NASA Great Observatories -- Hubble Space Telescope, Spitzer Space Telescope, and Chandra X-ray Observatory -- have produced a matched trio of images of the central region of our Milky Way. Stargazing on Mount Diablo Mount Diablo Astronomical Society (MDAS) Event Calendar The Mount Diablo Observatory Association, Inc. (MDOA) is a cooperating organization within Mount Diablo State Park. Incorporated in 1988, MDOA members planned, raised funds and established an astronomical observatory. The observatory consists of a Solar powered 96 square foot roll-off roof observatory, and a 500 square foot warming room. The heart of the observatory is a computer controlled Celestron 14, which has a variety of electronic attachments, a CCD camera, and photographic equipment. The addition of a refractor to the observatory has enhanced the photographic tasks and the public outreach of the observatory. A 15 Kilowatt generator provides all the electrical needs for lighting, heating, and AC for the comfort of our visitors in the warming room. At nearly 3800 feet above the mean sea level, the observatory has an unobstructed view of the night sky (and Mount Diablo is the highest mountain within the San Francisco Bay Area with a public access observatory). Every year MDOA and its sister organization, Mount Diablo Astronomical Society, operate Public Astronomy Programs under the sponsorship of Mount Diablo State Park. This program is now in its 28th year! For written information, applications for Associate Membership ($30/year; $25 annual membership + $5 MDAS name badge) to support the observatory or for other correspondence feel free to contact us by email, or in writing at: Mount Diablo Astronomical Society P.O. Box 4889 Walnut Creek, CA 94596 Celestron 14 | Jon Wilson Planetary Nebula, M 57 in Lyra. June 12, 2010 Information for Visitors: EXCITEMENT FOR THE WHOLE FAMILY! MOON Photographed April 13, 2009 Participate in hands-on astronomy activities followed by supervised observing through the many different telescopes of MDAS members. Bring snacks, water, binoculars, and warm clothes. If you bring a flashlight please cover it with red material. Please note that only Mount Diablo Astronomy Docents may set up telescopes on Public Nights. LOCATION DETAIL Mount Diablo, at the Lower Summit Parking Lot off Summit Road, almost to the top of Mount Diablo Summit Rd, Walnut Creek, CA 94598 More information at: Mount Diablo Astronomical Society Another astronomy link: Western Amateur Astronomers The material above is provided by Mount Diablo Observatory Association and Mount Diablo Astronomical Society

Geology Map of Mount Diablo Geologic Map Legend Quarternary - surficial deposits Quarternary - landslide deposits Jurassic/Cretaceous - dark greenish-gray shale sandstone interbeds (Knoxville Formation) Miocene/Pliocene - non-marine sandstone, siltstone, and conglomerate Miocene - marine fossiliferous sandstone and shale Jurassic/Cretaceous - melange (Franciscian Complex) Jurassic - chert and basalt with some graywacke and shale (Franciscan Complex) Miocene - silicic intrusive rocks Jurassic - basalt and diabase (Coast Range Ophiolite) Eocene - massive pebbly sandstone with shale Jurassic - serpentinite (Coast Range Ophiolite) Cretaceous - shale, siltstone, and sandstone (Great Valley Sequence) Silica carbonate rock (altered serpentinite) Thrust Fault Thrust Fault - inferred Fault Fault - Inferred Roads Streams Data Source Preliminary Geologic Map Emphazing Bedrock Formations in Contra Costa County, California. Compiled by R.W. Graymer, D.L. Jones, and E.E. Brabb U.S. Geological Survey Open-File Report 94-622 Arc/Info Data Files Simplified with minor modifications by Roi Peers and Craig Lyon, September 1996. Geologic Information Systems Map by Eric R. Sheehan, Martinez, California.

Mount Diablo State Park Weather and Air Quality Weather Mount Diablo Summit Weather Mount Diablo Summit Rainfall (CA.gov) Summit Webcam (CalFire) Mitchell Canyon Weather (Wunderground) Junction Weather (Wunderground) Air Quality Mount Diablo Summit AQI Junction Ranger Station AQI Mitchell Canyon Visitor Center AQI

Additional Resources Browse the resources available from our community partners. 1 California State Parks- PORTS Learning materials from the State Parks https://ports.parks.ca.gov 2 California Environmental Literacy Initiative Parent Portal http:// https://partnerportal.ca-eli.org/site/contra-costa-county-office-of-education/browse/community-based-partners 3 East Bay Parks Educator resources including Ohlone 3rd Grader Program, animals and field trips https://www.ebparks.org/programs/educators 4 Lawrence Hall of Science Programs including Stem Day, Otto Initiative, workshops on matter, circuits, life science, engineering, science kits, and resources for teachers including GEM kits. https://lawrencehallofscience.org/educators/ 5 Lindsay Wildlife Museum Discovery Kits, Hikes and Programs https://lindsaywildlife.org/teachers-and-schools/ 6 Mount Diablo State Park Interpreter-Led Programs Please contact Park Interpreter Sharon Peterson via email (Sharon.Peterson@parks.ca.gov ) for information regarding School Group Programs and/or Education Tours. Presented by California State Parks. https://www.parks.ca.gov/?page_id=517 7 Save Mount Diablo About the Mangini Ranch Educational Preserve and how to reserve a field trip. https://savemountdiablo.org/what-we-do/educating-and-inspiring-people/mangini-ranch-educational-preserve/ Next Generation Science Standards (NGSS) Back to Learn Download the NGSS Fact Sheet

Live Oak Campground Map

Ways to support Mount Diablo Interpretive Association Ways to Support MDIA Mount Diablo Interpretive Association is an all-volunteer organization dedicated to supporting Mount Diablo State Park. We are a 501(c)(3) organization, and our Tax ID# is 23-7444529. Donate Today! Gift Giving Make a donation to support the general operations of MDIA. Tribute gifts are also a way to remember or honor a loved one. Gifts can be one-time, or recurring. Employer Matching Gifts You can make your donation accomplish twice as much when you request a matching gift! Check to see if your employer can match your generous donation. Donate a Vehicle Donate your vehicle through Cars2ndChance and designate MDIA as the charitable organization. Cars2ndChance are vehicle / car donation programs administered by the Clayton Valley Concord Sunrise Rotary Charitable Fund and staffed by all volunteers. Become a Member MDIA counts on your support to provide docents for the visitor centers, sponsor the Junior Ranger program, guide hikes, and provide interpretive material and publications to park visitors. Support the Mount Diablo Education Center in Mitchell Canyon MDIA has officially launched a campaign to build a new Education Center at the Mitchell Canyon entrance to Mount Diablo State Park. Please join us in inspiring new protectors and champions of Mount Diablo by making a generous tax-deductible contribution today. Your gift will leave a legacy of education, protection, and wonder for the present and future generations! Gift of Stock Gifting stock is a simple and powerful way to support MDIA and the new Education Center at Mitchell Canyon. Required Mandatory Distribution If you have investments in 401k’s or similar instruments, and must take a distribution, you can direct your broker to send it to MDIA as a donation and not have to report it as income on your tax forms. Become a Volunteer Volunteering allows members to commit to as little as a couple of hours a week and still provide vital assistance to the association and park.

Mount Diablo Dragonflies and Damselflies A Preliminary Survey by Douglas Vaughan Berkeley, California May 2003 - May 2004 I conducted a preliminary survey of adult dragonflies and damselflies (Odonata) at Mount Diablo State Park between May 2003 and May 2004. During this period, I made 12 visits to the Park, surveying each of four different sites two to six times. I made no visits during April, September, or the period between mid-June and mid-July—nor during the winter months. Two tables summarize my findings. Several points underscore the preliminary nature of this survey: Unsurveyed sites, including Frog Pond on the south side of the mountain and Mitchell Canyon, might yield additional species. Pine Pond, the largest water feature in the Park and site of the greatest observed diversity, is surrounded by dense stands of emergent vegetation; a more aggressive survey that penetrated this vegetation and reached the main body of the pond might produce additional species there. During mid-season many dragonflies patrol meadows well away from water; I was unable to identify many of these insects. Great spreadwing, damselfly, Sulphur Springs Pond | Michael Marchiano Nonetheless, 25 of the 38 species currently known from Contra Costa County were found in the Park, including two observed only by others. I captured and examined in hand at least one individual of each of the 23 species I observed, except California Darner (Rhionaeschna [=Aeshna ] californica ), Common Whitetail (Plathemis lydia ), and Black Saddlebags (Tramea lacerata ), which were confidently identified in flight. Several additional species known from Contra Costa County seem likely to be present in the Park, especially Pacific and Black-fronted Forktails (Ischnura cervula and I. denticollis ), Aztec Dancer (Argia nahuana ), Exclamation Damsel (Zoniagrion exclamationis ), Western Pondhawk (Erythemis collocata ), Widow Skimmer (Libellula luctosa ), and Blue Dasher (Pachydiplax longipennis ). Indeed, I briefly observed a probable male Widow Skimmer in Donner Canyon but was not able to identify it with certainty. In addition, several species not yet found in Contra Costa County might be expected in the Park. Prominent examples include California and Emma’s Dancers (Argia agrioides and A. emma ), Twelve-spotted Skimmer (Libellula pulchella ), Wandering Glider (Pantala flavescens ), and Western Meadowhawk (Sympetrum occidentale ). The attached tables offer two presentations of the survey results. The annotated checklist indicates the dates on which the four sites were visited and the species found at each. The abundances indicated in the notes for each species should be taken as speculative. Species indicated as “uncommon,” in particular, might well be more common at other sites (or, say, within the perimeter of Pine Pond) or during periods I did not visit the Park. The second table provides a rough indication of seasonal distributions , though no conclusions should be drawn for species observed only once or twice. Note also that this table merges observations from March through mid-May 2004 with those of mid-May through October 2003. The dots in the four upper rows of the table indicate the approximate dates of visits to the four surveyed sites. In conclusion, Mt. Diablo supports a significant diversity of dragonfly and damselfly species, especially in light of the relatively few ponds and perennial streams within the Park. Particularly notable were the large numbers of patrolling darners (mostly Blue-eyed Darners) over the meadows well away from water during much of the spring and summer, and the striking abundance of Black Spreadwings during the first half of the season. Table I: Mount Diablo Odonata Annotated List Table II: Mount Diablo Odonata Seasonal Distribution * See Annotated List Source: Biologist/nature photographer David Liebman of Norfolk Below is a list of additional websites for information about dragonflies and damselflies: Virginia's Natural Heritage Program at http://www.vararespecies.org/ USGS Dragonflies and Damselflies of the United States: https://www.usgs.gov/science-explorer-results?es=dragonflies+and+damselflies Worldwide Dragonfly Association at https://worlddragonfly.org/ Digital Dragonflies at https://agrilife.org/dragonfly/ Odonata Information Network at http://www.dragonflies.org/ Catching and Preserving Dragonflies FAQ: http://dragonflywebsite.com/articles/collecting/morse2.html Dragonfly Biodiversity: https://www.pugetsound.edu/academics/academic-resources/slater- museum/biodiversityresources/dragonflies/