"Lake County owes its name to the presence of Clear Lake, which is one of the prominent geographical features of that section of the state. Mendocino and Glenn counties bound it on the north; Glenn, Colusa, and Yolo on the east; Napa on the south; Sonoma and Mendocino on the west. It has an area of 1328 square miles. Of the southern two thirds of the county the drainage is mainly into Clear Lake, except its outlet, Cache Creek, which flows southeastward into the Sacramento River. Putah Creek which also flows to the Sacramento, has its upper branches in the extreme southern part of Lake County. North of the Clear Lake system, the drainage forms the headwaters of the Eel River, which empties into the Pacific Ocean.
"Though Lake County has a variety of mineral occurrences and many interesting geological features, but two branches have been exploited or developed to any considerable extent: quicksilver and mineral water. There was also at one time a production of borax and of sulphur, but slight in amount and short duration.
"For a number of years quicksilver was the premier mineral in production for the county, but at the present time it has dropped to an almost insignificant figure, taking second place to mineral water. The greatest activity in quicksilver mining took place between 1875 and 1882, reviving again from 1891 to 1903; though the Abbott was a producer as early as 1870, the Great Western from 1873, and Sulphur Bank in 1874. The Mirabel (formerly Bradford), another important producer, was opened in 1887, but has been abandoned since 1897.
"In addition to the above, there are also occurrences of barytes, chromite, copper, kaolin, gold, silver, manganese, natural gas, mineral paint, limestone and 'onyx-marble,' also some petroleum seepages; none of these, however are at present utilized commercially.."
"Except for occasional local uses, there has been no development of the stone industry in Lake County (as of 1913-1914). The board of supervisors reported macadam to a value of $10,000 used on road work in 1908, but they have done nothing but minor repairs since that time. There is said to be a red volcanic rock near Lower Lake which makes an excellent macadam, particularly when mixed with some clay."
Area: 1,278 square miles.
Population: 5,542 (1920 census)
Location: About fifty miles north of San Francisco Bay and the same distance inland from the Pacific Ocean.
"On account of its topography and natural beauties, Lake County is sometimes referred to as the Switzerland of America. The mineral resources which exist here are many and varied, actual production being comparatively small, as shown by the table below, and composed mainly of quicksilver, and mineral water. Some of the leading minerals, found in this section, in part as yet undeveloped, are borax, chromite, clay, copper, gems, gold, gypsum, mineral water, quicksilver, silver, and sulphur.
"In forty-ninth place, commercial production for 1919 was as follows:"
(Headings for the information below are: Substance, Amount, and Value.)
Mineral water, 62,839 gals., $17,471
Quicksilver, 229 flasks, $20,604
Stone, miscellaneous, ---, $1,200
Other minerals, ---, $100
(Total value) $39,375
"Lake County - Mines and Mineral Resources of Lake County," by Charles V. Averill, Mining Engineer, California State Division of Mines, Ferry Building, San Francisco. Manuscript submitted for publication October 10, 1946.
General Description of the County (Lake County)
"Lake County lies due north of San Francisco at a distance by road of 100 miles. Mendocino County, which is about 40 miles wide, lies between Lake County and the Pacific Ocean. Lakeport on the shore of Clear Lake is the county seat and the largest town. Upper Lake, Kelseyville, Lower Lake, and Middletown are smaller towns in the Clear Lake vicinity. The total population of the county by the 1940 census was 8,069 persons. The land area is 1,256 square miles.
Topography (of Lake County)
"Clear Lake, a body of fresh water 19 miles long and 2 to 8 miles wide, with a maximum depth of 50 feet, lies near the center of the county. This lake now occupies part of a basin that was formerly drained by two streams, Cold Creek, flowing westward to the Russian River, and Cache Creek, flowing eastward to the Sacramento River. Cache Creek was crossed near its gorge entrance by a small lava flow, but later a landslide cut off Cold Creek and caused the water of Clear Lake to rise higher than the surface of this lava flow. Thus drainage to the Sacramento River was reestablished, but drainage to the Russian River is now cut off. The Blue Lakes occupy parts of the gorge through which the basin of Clear Lake was formerly drained by Cold Creek. The more mountainous northern part of the county is drained by Eel River. Elevations range from 1,340 feet above sea level at Clear Lake to over 7,000 feet at Snow Mountain.
Climate (of Lake County)
"The climate is mild, without extremes of either heat or cold; and falls of snow are common only at the higher elevations. Annual rainfall is about 35 inches. The pleasing summer climate and the attractive mountain and lake scenery draw many people to the numerous summer resorts. Hunters and fishermen also find the climate and the mountains, lakes, and streams much to their liking.
Transportation (in Lake County)
"Lake County has no railroad service and is dependent entirely on state highways, county, and private roads for transportation. Winding over the mountain at an easy grade, a good highway crosses Mount St. Helena on the southern county line, and connects Calistoga, the railroad terminus in Napa County, with Middletown, Lake County. A similar highway connects Lakeport with Hopland to the west. A still better highway with easier grades connects Ukiah, Mendocino County, with Upper Lake, runs along the north shore of Clear Lake, thence to Williams in the Sacramento Valley. This is a part of the Ukiah-Tahoe state highway. A number of other all-weather roads reach such points as Kelseyville and Lower Lake, but many other points are reached only by means of graveled or dirt roads. Small boats are operated between points on the shore of Clear Lake, chiefly for pleasure.
Industries (in Lake County)
"Agriculture is the main industry in Lake County. Bartlett pears, walnuts, almonds, prunes, apples, grapes, and olives are important; and oranges, figs, berries, melons and other fruits are grown. Other important crops are wheat, barley, corn, oats, beans, alfalfa, and hops. The livestock industry flourishes, the higher mountains furnishing abundant summer range, the foothill country and alfalfa fields taking care of the stock in the winter. Practically all of Lake County north of Clear Lake is in the California National Forest, which extends northward into the southern part of Trinity County. In this entire forest are 4,000,000,000 feet of pine and fir timber on government land, and 2,000,000,000 feet on private land. Chamiso brush occurs in dense stands in this forest up to elevations of 3,500 and 4,000 feet. Above this are fine stands of pine and fir. Extensive areas of scrub white oak are characteristic of the region. The mature government timber is available for sale under competitive bids; but, on an account of the lack of suitable transportation within the forest, no large sales have been made. The forest is the best stocked deer region in California, and is a favorite with sportsmen. The Columbian black-tail dear abound in the brush as well as in the timber belt.
"The summer-resort business is a thriving one in Lake County. The mineral springs with their hotels and baths form one type of resort; the lake resorts with fishing, swimming, and boating make up a second type; and the mountain camps with their attractions of hunting and fishing form a third type. Several tracts of land near Clear Lake have been subdivided into lots and sold as sites for summer homes.
Geology and Mineral Deposits (in Lake County)
"The geologic map of California* shows that Franciscan (Jurassic) sediments predominate in Lake County. They have been intruded by large dikes of ultrabasic rocks now altered to serpentine. The volcanic rocks in the vicinity of Clear Lake form a prominent feature of the geology. They have been described in detail by Anderson** who has also published a detailed map of the volcanic rocks south and east of Clear Lake.
(* Page 17, footnote 2: Jenkins, Olaf P., Geologic map of California, scale 1:500,000: California Div. Mines, 1938.)
(** Page 17, footnote 3: Anderson, Charles A., Volcanic history of the Clear Lake area, California: Geol. Soc. America, Bull. 47, pp. 629-664, 6 pls., 8 figs., 1936.)
"Minerals of commercial importance are associated with the igneous rocks. A little chromite and manganese ores has been produced, but the important production has been that of quicksilver; and high prices during the war of 1941-45 stimulated production of that liquid metal. Late in 1945, production of quicksilver was much lower because of declining prices. Mineral springs continue to be of importance both as sources of water for bottling and as centers of attraction for resorts."
Stone for Building (in Lake County)
"Many types of stone of volcanic origin that have been used for buildings are available in Lake County...."
"According to Henry Mauldin, chairman of the Board of Supervisors, Lakeport, abundant stone suitable for stepping-stones is found in sec. 20, T. 12 N., R. 8 W., M.D., near Boggs Lake. In SE ¼ sec. 8, T. 12 N., R. 8 W., M. D., is a light-colored rock resembling petrified wood that has been used as ornamental stone in columns, walls, and rock gardens. Cobble-stones for walls and other construction have been obtained from Kelsey Creek 1 ½ to 6 miles south of Kelseyville and from Adobe and Highland Creeks, 3 to 5 miles southwest of Kelseyville. At a point 2 miles due west of Highland Springs, in sec. 35, T. 13 N., R. 10 W., M.D., on property owned by Dr. Neal C. Woods of Lakeport, is a hill of a dark gray rock that has been used in the construction of several buildings in Finley and on farms in the vicinity.."
Stone Industry (in Lake County)
"Except for occasional local uses, there has been no development of the stone industry in Lake County (circa 1913). The board of supervisors reported macadam to a value of $10,000 used on road work in 1908, but they have done nothing but minor repairs since that time. There is said to be a red volcanic rock near Lower Lake which makes an excellent macadam, particularly when mixed with some clay."
"Small quantities of lime were burned in Lake County for local use, especially at the quicksilver-reduction plants. No large deposits are known to occur in the county. Lake County has no railroad lines and the population in 1940 was slightly over 8000.
"Some limestone has been reported near the Abbott quicksilver mine, near the east county line in the southwest part of T. 14 N., R. 5 W., M.D. In Burns Valley, near the present Clear Lake Park, lime kilns were once operated. Occasionally masses of limestone may be found loose in this region. Limestone occurs in sec. 19, T. 11 N., R. 7 W., M.D. There are the remains of an old stone lime kiln in sec. 36, T. 13 N., R. 6 W., M.D., which was used many years ago to burn limestone from a small deposit nearby."
"Lake County, isolated in the Coast Ranges 80 miles north of San Francisco Bay, experienced a local mining boom in the nineteenth century. It was there that the first borax produced in the United States was extracted (1864), as well as the first California sulphur (1865), and a tenth of California's quicksilver. Moreover, the many hot and cold mineral springs in Lake County's Chamise and pine covered hills soon attracted thousands of eager health seekers who willingly braved the rough, dusty stagecoach ride to the many resorts that sprang up. By the eighties Lake County resorts had developed into considerable establishments renowned throughout northern California for the reputed effectiveness of their waters. At the close of the century Lake County was a thriving resort area though mining, after disheartening setbacks, was at a low ebb.."
Mining History (in Lake County)
"In its pioneer period Lake County was noted not for its agriculture, but for its mines and mineral springs, the most important of which were in the southern half of the county. The Lake County quicksilver mines first came into production in 1870 and throughout this era quicksilver mining continued to have an important influence on the economy of the county. It was in the mining of borax and sulphur, however, that Lake County attracted most attention in its earliest mining days. Here, in 1864, the United States' first borax was manufactured (Bailey, 1902, p. 33), and a year later California's first sulphur was extracted (Jenkins, 1950, p. 274)...."
(* Please note this list does not include sand or gravel quarries.)
Big Valley, Lake County, California – Stone Quarry on Mount Konocti or “on Uncle Sam” (Rholitic Obsidian)
The following information is from Lake County Illustrated and Described Showing Its Advantages for Homes, W. W. Elliott, Lithographer and Publisher, Oakland, Cal. 1885, pp. 82, 85. (Available on PDF in Google Books - Full View Books)
“Among the first ranches in Big Valley, Lake County, that of Mr. W. N. Thompson is particularly noticeable, not only for the position which it occupies in this rich agricultural section, but also for the substantial and elegant improvements which the owner has recently made….”
“The buildings on the place consist of a fine new residence and three barns….”
“Two fine fire-places in the building are built of hewn stone, procured from a quarry on Uncle Sam, or Mount Konocti. This quarry is quite famous in Lake County, being situated about one and one-half miles from Kelseyville, and is in considerable demand for constructing fire-places, the stone being of a quality which is not injured by the action of heat….”
I have not been able to find any additional information on this quarry on Mount Konocti, although I found the following entry relating to the Uncle Sam quicksilver mine, which is also located near Konocti Mountain. If you have any further information on this quarry, I would like to hear from you Peggy B. Perazzo.
Twelfth Report of the State Mineralogist (Second Biennial), Two Years Ending September 15, 1894, California State Mining Bureau, pp. 362.
“Uncle Sam Mine – It is 10 miles N.W. of Lower Lake, near Konocti Mountain, and comprises three (quicksilver) claims. It is a mere prospect; the indications show low-grade ore, and extend over a width of about 400 ft. in serpentine. A. A. Gibson, of Lower Lake, owner.”
"A nearly white fine-grained tuff has been quarried a quarter of a mile due north of the main buildings at Seigler Springs and has been used in building construction at the springs. A similar deposit in sec. 30, T. 12 N., R. 7 W., about 2 miles to the southeast of the one first mentioned, is a quarter of a mile south of Bonanza Springs on property owned by Edward Stahl, 1600 Market Street, San Francisco. To the east of this bluff at a distance of 500 feet, the tuff outcrops along an old road, but it is not consolidated here and is more of the nature of sand. These tuffs are soft and easily worked when freshly quarried but harden after exposure. Similar tuff has been quarried in sec. 23, T. 13 N., R. 9 W. near Kelseyville; also at another quarry near Middletown."
"There is limestone near the Abbott quicksilver mine, and at Burns Valley north of Lower Lake. At the latter, the Sulphur Bank Mine Company at one time had two kilns, but nothing has been done there for about twenty years past.
"Bibl.: R. XII, p. 392; R. XIII, p. 629."
"Near Clear Lake Park, sec. 16, T. 13 N., R. 7 W., W. D., is a colored vesicular lava that has been used for the foundations of buildings at Clear Lake Highlands. The color is various shades of red and brown caused by hematite. A few truck-loads of this stone have been shipped to the San Francisco area. No quarry has been opened; the stone used thus far has been loose chunks from the surface. The deposit is on the ranch known as the Mott place assessed to Charles N. Reid and others, Clear Lake Park. Similar rock is found on the shore of Clear Lake on land owned by W. Henderson of Kelseyville, in sec. 5 T. 13 N., R. 8 W. This occurrence is accessible only by boat; small amounts of the rock has been used."
"A white rock on Bottlerock road in 7, T. 12 N., R. 8 W., M. D., about 7 miles from Kelseyville, appears to be a rhyolite or possibly a highly indurated tuff.About a quarter of a mile up the road and the same distance to the southwest, in sec. 18, T. 12 N., R. 8 W., M.D., is a gray rock, probably andesite, reached by a quarter-mile of old rock in poor condition. This breaks on joints into slabs 2 to 3 inches thick and has been used for stepping-stones.."
".At a sharp bend in the Bottlerock road, 5 miles from Kelseyville or 2 miles from the point where this road leaves State Highway 29, an old road leads to the foundation of an old hotel that was built of local stone at a distance of only a few hundred yards from the Bottlerock road. The stone is almost like obsidian but is cryptocrystalline. Most of the stone in the immediate vicinity, sec. 1, T. 12 N., R. 9 W., M. D., is obsidian."
“A white rock on Bottlerock road in 7, T. 12 N., R. 8 W., M. D., about 7 miles from Kelseyville, appears to be a rhyolite or possibly a highly indurated tuff…About a quarter of a mile up the road and the same distance to the southwest, in sec. 18, T. 12 N., R. 8 W., M.D., is a gray rock, probably andesite, reached by a quarter-mile of old rock in poor condition. This breaks on joints into slabs 2 to 3 inches thick and has been used for stepping-stones….”
Mine name: Sulpher Mound Mine; Operator: S-Bar-S Quarry; Address & County: P.O. Box 3818, Santa Rosa, CA 95402, Lake County; Phone: (707) 579-5717; Latitude: 38.93, Longitude: -122.76, and Mine location number: Map No. 281; Mineral commodity: Decorative rock.
(Excerpt from the web site) “Lunch on the shore at Soda Bay was followed by a jaunt to the southern tip of Clear Lake to the aggregate quarry at Round Top Mountain. Round Top is a small, very recent basaltic andesite cinder cone dissected by the quarry operation….” (Photo caption) “Looking for xenoliths at the quarry.”
"A nearly white fine-grained tuff has been quarried a quarter of a mile due north of the main buildings at Seigler Springs and has been used in building construction at the springs in sec. 24, T. 12 N., R. 8 W., M. D. A similar deposit in sec. 30, T. 12 N., R. 7 W., about 2 miles to the southeast of the one first mentioned, is a quarter of a mile south of Bonanza Springs on property owned by Edward Stahl, 1600 Market Street, San Francisco. The stone is somewhat coarser in grain here, and the different strata exhibit various shades of white, gray and buff. The stone stands as a bluff 75 feet high and 100 feet long. A few of the fragments in the tuff are half an inch in diameter, but the general grain is much finer...."