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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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Contact Us If you have any questions or suggestions about our Privacy Policy, please contact us .

MDIA Board Members Steve Smith . . . . . . . President Mike Brandy. . . .Vice President Dan Sandri . . . . . . . . .Secretary Dan Fitzgerald . . . . . Treasurer Mark Brauer Julie Braun Martin Leslie Contreras Tere Dixon Linda Kwong Carol Lane Dick Nicoll Steve Viarengo Steve Smith President Steve grew up in Danville and has been an avid hiker and outdoor enthusiast his whole life. He is a docent, hike leader, back-country rover, leader of the Maintenance Volunteer Group, and member of the Trash Removal Project. He began volunteering on the mountain after completing a quest to hike all 162 miles of trails within the park. Mike Brandy Vice President Mike is always drawn to the outdoors for inspiration and renewal. As a Mount Diablo State Park volunteer for the last four years, he is currently engaged in co-managing the Mitchell Canyon Visitor Center, always trying to enhance the docent training and the visitor experience to the park. He also volunteers on the Trash Removal Project (TRP) team. He usually cycles or hikes every week on the mountain. Dan Fitzgerald Treasurer Dan grew up in Concord with a view of the mountain and spent some time exploring it with Michael Marchiano. When he retired, Dan completed the State Parks volunteer training and became an active member of the Trash Removal Project and a visitor center and roving docent. Dan also enjoys nature photography. Dan Sandri Secretary Dan has lived in the East Bay for nearly all of his life, and Mt. Diablo has always been his favorite hiking place. Dan has a B. S. degree in Entomology and enjoys observing and photographing insects, birds, reptiles, as well as other plant and animal life. Upon retirement, Dan became a volunteer at Mitchell Canyon Visitor Center, and a back-country rover. Dan enjoys interacting with visitors, learning and writing. Mark Brauer Mark has lived in the East Bay for the last 35 years and has enjoyed hiking at Mount Diablo since he moved here. For the past six years he has volunteered his time as a docent and as a rover at Mount Diablo. He particularly enjoys interacting with the park's visitors and helping them discover the best places to visit in the park. Mark set himself the goal in 2013 to hike every trail in Alameda and Contra Costa counties and after 8 years completed that task. Of all the parks and open spaces in the East Bay he finds the most enjoyment from visiting Mount Diablo. Julie Braun Martin Julie, an educator for many years with a passion for conservation and serving youth, enjoys walking on the mountain and serving at Mitchell Canyon and assisting with publications. Leslie Contreras Living in the shadow of Mount Diablo all her life, Leslie has always had a passion for the mountain. She contributes to MDIA as the event coordinator for the hiking program and as co-manager of the Mitchell Canyon Visitor Center. Terese Dixon Tere has lived at the base of Mount Diablo for nearly 40 years and has hiked and biked the trails of Mount Diablo State Park throughout that time. Currently serving as the Webmaster for the MDIA website , Tere is also a State Park volunteer, and is a California Naturalist. Other than cycling with her husband, Tere enjoys working in her dry garden and birding. Linda Kwong Linda has lived in Alamo since 1997. Her connection to the mountain started after a neighbor took her on a bike ride to the Summit over 7 years ago. Now she is a regular visitor on the mountain, often riding 3-4 days per week. Photographing all four seasons and engaging with both the park visitors and staff are her favorite activities. Her goal is for all park visitors to have a safe, memorable and fun experience during their visit on Mount Diablo. Carol Lane Carol is a retired Registered Nurse who loves to be active and find interesting things out in nature. She is an active trail maintenance volunteer and sees trail work as a way to give back for the enjoyment that she experienced as a trail runner. Dick Nicoll A long time local resident, Dick loves everything outdoors. He coordinates publications, serves at Mitchell Canyon, works on the Trash Removal Project, and organizes road repairs. He has completed the California Naturalist Program. Steve Viarengo Steve has been a Danville resident since 1997. In that time he has spent many hours hiking and biking on Mount Diablo and enjoying time with his family exploring Rock City. He began volunteering in 2022 and found that the volunteer activities he enjoyed the most involved being with visitors out in the park. In addition to time on the trails he enjoys kayaking on Lake Tahoe and traveling with his wife. MDIA Committee Members and Leads Archives Lead(s): Dan Sandri Other Members: Steve Smith Maintains print archives Audible Mount Diablo Lead(s): Steve Smith Other Members: Wally De Young; Kendall Oei; Joan Hamilton Coordinates development of Audible Mount Diablo/Mount Diablo "Shorts" Contracts Lead(s): Dick Nicoll Other Members: Steve Smith Develops and reviews MDIA contracts Corporate Governance Lead(s): Vacant Other Members: Dan Sandri Updates and maintains the documents contained within the MDIA Board of Directors Handbook Education Lead(s): Julie Braun Martin, Dick Nicoll Other Members: Encourage school field trips by adding content to MDIA website that would assist teachers in planning trips to MDSP. Finance Lead(s): Dan Fitzgerald Other Members: MDIA Executive Committee Review financial records and bank statements Fundraising Lead(s): Mike Brandy, Dick Nicoll, Julie Braun Martin Other Members: Judith Parker, Gary Parkhurst, Dan Sandri, Steve Smith, Steve Viarengo, Tere Dixon Develops fundraising strategy to support new MCVC Hikes Lead(s): Leslie Contreras Other Members: Ken Lavin Recruits hike leaders; advertises and leads hikes in the park Insurance Lead(s): Linda Kwong Other Members: Negotiates appropriate insurance coverage and manages insurance-related matters Interpretive Displays Lead(s): Steve Smith Other Members: Mike Brandy, Dick Nicoll, Mark Brauer, Julie Martin Designs and fabricates interpretive panels and visitor center displays in conjunction with MDSP MCEC Capital Committee Lead(s): Mike Brandy, Dick Nicoll Other Members: Julie Braun Martin, Steve Smith Recommend architects to prepare conceptual drawings for new MCVC; apply for grants for MCVC Marketing, Advertising and Publications Lead(s): Dick Nicoll Other Members: Steve Smith Publishes Mount Diablo Review , MDIA annual report, and other MDIA publications Membership Lead(s): Julie Braun Martin Other Members: Steve Smith, Dan Fitzgerald, Dick Nicoll Maintains membership list; prepares membership packets and acknowledgements. Merchandising Lead(s): Dan Fitzgerald, Steve Smith Other Members: Linda Kwong (wholesale); Steve Smith(online); Dan (Perishables) Orders and maintains merchandise to sell at SVC, MCVC and online; maintains inventory; fulfills online orders Mountain Talks Lead(s): Mike Brandy Other Members: Steve Smith Develops program and presents Mountain Talks Native Plant Garden Lead(s): Carol Lane Other Members: Carole Leadem; Leslie Contreras; Judy Quinlan; Mary Jankowski Maintains, repairs and replants native garden at MCVC Nominating Lead(s): Mark Brauer Other Members: MDIA Executive Committee Recruits and nominates board members and officers Outreach Lead(s): Mark Brauer Other Members: Steve Smith Develop and maintain relationships with external partner groups and community Park Maintenance (MVG/TRP) Lead(s): Steve Smith Other Members: Dan Fitzgerald Coordinates with MDSP the repair and improvement of parks structures and the removal of non igneous material from the park Peregrine Team Lead(s): Vacant Other Members: Leslie Contreras, Steve Smith Educate public and monitor the status of the falcons throughout the nesting season. Recruitment Lead(s): Linda Kwong, Leslis Contreras Other Members: Develop a strategy to increase diversity of MDIA board Trail Maintenance Lead(s): Carol Lane Other Members: Coordinates MDIA sponsored trail maintenance activities and budget Trail Signage Lead(s): Steve Smith Other Members: Dan Fitzgerald Coordinates trail sign maintenance and installation with MDSP Volunteers in Park Lead(s): Dan Fitzgerald Other Members: Budget item only: for budget requests from MDSP for VIPP Website and Social Media Lead(s): Terese Dixon, Steve Viarengo Other Members: Steve Smith Designs, updates, and maintains the MDIA website and social media presence

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

Much of the rock that makes up Mount Diablo is sedimentary in origin. It was laid down millions of years ago on the floor of the ocean. Within the last one to two million years, a piece of hard, red 160-million-year-old Franciscan rock was pushed up through six to eight miles of overlying rock and soil, tilting and distorting the rock layers and in some places turning them completely upside down. As a result, the fossilized remains of many sea creatures, as well as those of mastodons, saber-toothed cats and three-toe horses have been discovered here ___ Mount Diablo State Park brochure Plants Geology Wildlife Astronomy Natural History of Mount Diablo State Park

Volunteering with MDIA for California State Parks Get Involved Mount Diablo Interpretive Association and Mount Diablo State Park Volunteer Programs 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. If you are interested in any of these opportunities and would like more information, please email us. Dan Cook Canyon bridge crew Information & Sales volunteers Volunteer leading hike Dan Cook Canyon bridge crew 1/4 MDIA and Mount Diablo State Park offer MDIA members and the public volunteer opportunities in the park and in MDIA operations. The association encourages all its members to become involved in MDIA's growth and in park activities. The State Department of Parks and Recreation sponsors the Volunteers In The Parks Program (VIPP) to provide organized and effective use of volunteers, including recognition for their contributions to state parks. The work of volunteers is highly appreciated and is necessary to maintain the parks in California. All volunteers in the park are required to complete several hours of training given at the park by park staff. For more information about the VIPP program, contact VIPPMountDiablo@parks.ca.gov Volunteer opportunities available Docent at the Summit Visitor Center or Mitchell Canyon Visitor Center. MDIA and Mount Diablo State Park are recruiting for volunteers to serve as Park Docents. Park Docents staff the Summit and Mitchell Canyon Visitor Centers and hike trails as roving docents. Docents provide information to park visitors and sell merchandise on behalf of MDIA. Docents usually work 3 to 4 hour shifts. Guide scheduled hikes for visitors. MDIA schedules public hikes throughout the year. We are always looking for interested individuals to lead or assist with these hikes. Back Country Patrol. Volunteers hike, bike, or ride horseback on trails in the park, reporting any issues and helping to interpret the park. Note that special training is required to assist with visitor emergencies. Trail Crew. Interested individuals are invited to join the Mount Diablo Volunteer Trail Crew program to assist in maintaining park trails. MDIA committee member. MDIA has many active committees, including outreach/publicity, publications, merchandising, trail adoption, and trash removal. These committees often sponsor activities and are always looking for volunteers to help. MDIA board member. Periodically, MDIA recruits board members. Board members commit to meeting once a month as well as serving as committee leads and participating in MDIA activities. 1. 2. 3. 4. 5. 6.

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

Butterfly Identification Guide Skippers Hesperiidae: Small to medium-sized with large muscular bodies relative to wing size and rather broad heads. The common name refers to the mode of flight and they sometimes engage in dazzling aerobatics. Blues, Coppers, Hairstreaks Lycaenidae: The largest family, these are small to medium sized with fragile-looking wings. Males have moderately reduced forelegs and the base of the antenna is adjacent to the compound eye. Brushfoots Nymphalidae: A very large family with subfamilies which are diverse in appearance and biology which argues for them to be families on their own. The common name refers to forelegs which are reduced and brushlike. Swallowtails Papilionidae: One of the most thoroughly studied families. Contains many of the most spectacular and charismatic butterflies. Whites and Sulfurs Pieridae: Our butterflies are mostly medium-sized and colored white, yellow or orange with black markings. Metalmark Riodinidae: Closely related to Lycaenidae, the common name refers to brilliant metallic markings. Our concepts of relationships between and within these families, although based upon phylogenetic* knowledge, continue to evolve rapidly especially influenced by molecular evidence. *Phylogenetics - How recently did two species share a common ancestor using observable traits and molecular science genetics. Quicklinks Butterflies A - Z Butterfly Checklist (PDF) Over 60 species of butterflies are known to live on Mount Diablo, which is almost 50 percent of all known species in the San Francisco Bay Area. When looking for butterflies, choose a sunny day with a temperature above 65 degrees Fahrenheit, generally between 10 a.m. and 3 p.m. Very few butterflies fly when it is cool, foggy, or rainy. Binoculars that can focus 10 feet or closer are very useful. In keeping with the California State Parks mission statement, butterflies and their habitat are protected, and collecting of butterflies is strictly prohibited in Mount Diablo State Park. MDIA welcomes input on sightings or other information that you may wish to contribute. Please contact MDIA at info@mdia.org .

Trail Through Time A Journey Through 180 Million Years of Geologic Time Parking access at Rock City, Sunset Picnic Area, Juniper Campground and Lower Summit Parking Lot Introduction With 20 trailside interpretive panels, the complete Trail is 6.25 miles in length with a vertical elevation gain of 2,940 feet. It can also be traversed in reverse down the mountain walking over older to younger rocks. Because the panels are independent of each other, shorter segments of the Trail can also provide an informative geology experience. A Geologic Story Book Like chapters in a book, the rocks of Mount Diablo tell a story of previous landscapes, climates, and life forms as well as epic journeys of tectonic plates. Trail Through Time panels are placed along the trail to help you read the geologic story written in the rocks as you travel through 180 million years of geologic time. Interspersed with the geologic panels are panels on history, geography, and ecology. The Journey Begins Your journey back in time begins near the southern park boundary on Sycamore Creek. As you walk north toward the mountain, you will first journey over 12 million-year-old rocks formed in a shallow sea. Look for shell fossils as you walk. At Rock City, you will pass over 50 million year-old sandstone with unusual erosion features, such as the Wind Caves and Sentinel Rock. You will then cross a rock bed exposing numerous marine snail fossils. When Reptiles Ruled Continue your journey as you cross over the boundary between the “Age of Mammals” into the “Age of Reptiles.” In a short distance you will cross a major fault along which the core rocks of the mountain have been pushed up and over younger rocks. As you continue to climb toward the summit, you pass the former site of a hotel built in the late 1800’s. Walking over Older Rocks As you walk among the varied and oldest rocks of the mountain’s core, you will find contorted red beds of chert made from the skeletons of tiny marine animals, followed closely by an exposure of graywacke sandstone. A short distance ahead is an outcrop of greenstone, an altered submarine volcanic rock. The chert, graywacke, and greenstone rocks have undergone massive compressive forces. The Journey Ends At the end of the Trail Through Time is an overlook to the north with a view over displaced igneous rocks that were originally formed as ocean crust at a distant spreading center. The spectacular view from the summit makes your climb all worthwhile. Download the Trail Thru Time PDF The DEDICATION CEREMONY for the Trail Through Time was held in the Fall of 2008. Work will continue to upgrade the trail alignment and develop outreach programs to encourage public use. We invite suggestions from trail users to help us improve the value of the trail as an educational and hiking experience. California State Parks does not discriminate against individuals with disabilities. Prior to arrival, visitors with disabilities who need assistance should contact the park at the phone number below. To receive information in an alternate format, write to the following address: Mount Diablo State Park 96 Mitchell Canyon Road Clayton, CA 94517 (925) 837-6119 TTY relay service, 711 www.parks.ca.gov Brochure compiled by Mount Diablo Interpretive Association in conjunction with California State Parks, University of California Museum of Paleontology, and the National Natural Landmark Program of the National Park Service. In recognition of the mountain’s importance to our natural landscape, a state park was established in 1931. It was designated a National Natural Landmark by the National Park Service in 1982.

Wetland Brewer's Blackbird Euphagus cyanocephalus Cliff Swallow Petrochelidon pyrrhonota Killdeer Charadrius vociferus Mallard Anas platyrhynchos Northern Harrier Circus hudsonius Red-winged Blackbird Agelaius phoeniceus Song Sparrow Melospiza melodia

Wildflower Mount Diablo Morning Glory, Sierra False Bindweed Scientific Name: Calystegia malacophylla ssp. pedicellata Family: Convolvulaceae (Bindweed Family) Blooms: May - Jun Color: White Perennial herb Native, endemic to California Jump to Blooming Now Blue / Purple Red / Pink White Yellow / Orange Invasive Plants Donna Pomeroy, iNaturalist

Diggers, Bumbles, Longhorn, and Nomad Bees Black-tailed Bumble Bee Bombus melanopygus January - July (rarely as early as December) Read More California Bumble Bee Bombus californicus February - September Read More Yellow-faced Bumble Bee Bombus vosnesenskii January - September Read More Foothill Carpenter Bee Xylocopa tabaniformis orpifex Later March - June Read More Small Carpenter Bee Ceratina March - July Read More Valley Carpenter Bee Xylocopa sonorina March – September (Uncommon on Mount Diablo) Read More California Digger-cuckoo Bee Brachymelecta californica June - August Read More Edwards Melectum Melecta edwardsii March - early June Read More Lovely-tailed Mourning Bee Melecta separata callura March - May Read More Nomad Bees Nomada February - June Read More California Digger Bee Anthophora californicus February - May; there may be a Fall generation too Read More California Mountain Digger Bee Habropoda depressa February - early June Read More Edwards Digger Bee Anthophora edwardsii Earlier Spring (starting late-February/early March) Read More Pacific Digger Bee Anthophora pacifica February and March - not common. Read More Urbane Digger Bee Anthophora urbana Late Spring - Early Fall Read More Eucera Longhorn Bee Eucera March to June Read More Melissodes Longhorn Bee Melissodes Late Summer to Fall Read More Bindweed Turret Bee Diadasia bituberculata April to June Read More

Resin Bees Dark Bees Stelis April - June Read More Ashmeadiella Ashmeadiella Summer Read More California Rotund-Resin Bee Anthidiellum notatum robertsonii May - August Read More Chelostoma californicum Scissor Bee Chelostoma californicum April - June Read More Hoplitis Mason Bee Hoplitis April - early June. Read More Prong-faced Slender-Mason Bee Protosmia rubifloris April - August Read More Megachile Leafcutter Bee Megachile Summer Read More Osmia Mason Bee Osmia Primarily April - June, but Osmia ribifloris biedermannii appears from January. Read More Dianthidium Dianthidium Late May - August Read More California Resin-Leafcutter Bee Trachusa perdita April - June Read More