Area: 447 square miles.
Population: 36,781 (1920 census).
Location: Peninsula, adjoined by San Francisco on the north.
"San Mateo's most important mineral products are stone, and salt, the last-named being derived by evaporation from the waters of San Francisco Bay. The total value of all mineral production during 1919 equaled $241,671, as compared with the 1918 figures of $193,812.
"Small amounts of barytes, chromite, infusorial earth, and quicksilver have been noted in addition to the items of economic value given below. Bricks have also been produced commercially.
"In thirty-sixth place, commercial production for 1919 was as follows:
(Headings for the information below are: Substance, Amount, and Value.)
Salt, 30,238 tons, $136,190
Stone, miscellaneous, ---, $42,235
Other minerals,* ---, $63,246
(Total value) $241,671.
(* Includes magnesium salts and potash.)
"The geology of San Mateo County has been shown in the San Francisco and Santa Cruz folios of the U. S. Geological Survey. The areal geologic mapping of the first-named folio was done largely by students and instructors in geology in the state university, and for the Santa Cruz folio much work was carried on by similar groups from Leland Stanford Junior University. As might be expected, the work was therefore done in adequate detail and under supervision of well-known geologists familiar with the areas.
"The pre-Franciscan (Gabilan) limestone occurs as inclusions in the quartz diorite commonly called 'Montara granite.' Only one such occurrence has been mapped that is of possible commercial size. It is 1 ½ miles west of Crystal Springs Reservoir on the west side of the Pilarcitos fault in W ½ sec. 11, T. 5 S., R. 5 W., M.D.
"The foraminiferal Franciscan (Calera) limestone outcrops in association with more or less chert, from the shoreline at Rockaway Beach in 2 narrow interrupted bands half a mile to 1 mile apart, which extend southeast for 11 miles on the east side of Pilarcitos fault. In this county the limestone has been utilized principally as crushed rock, and has been quarried over a long period of time at Rockaway Beach.
"Some unusual occurrences of Eocene limestone are shown on the Santa Cruz folio at Langley Hill and Mindego Hill, 2 miles northeast and 3 miles southeast, respectively, from La Honda. They are described as clastic dikes, varying in width from less than 1 inch to over 30 feet, and up to 150 feet long, enclosed in tuff underlain by diabase.
"By far the most important limestone deposits in the county are the Recent accumulations of oyster, clam, and mussel shells on the floor of south San Francisco Bay, between Millbrae and Alviso. These are being used in large quantities for making cement, and also for agricultural limestone.
"Notes of limestone quarries being worked to supply crushed rock have been supplied through the courtesy of Henry H. Symons, Assistant Mining Engineer of the Division of Mines."
(* Please note this list does not include sand or gravel quarries.)
"Gardner Quarry; Dr. A. M. Gardner, Belmont, owner. One half mile west of Belmont. the rock is a folded and crushed chert. The quarry has been worked in three different faces, and is operated intermittently."
"Johnson-Splivalo Quarry, half a mile northwest. The rock is a red and white chert, and is highly stained with manganese. It occurs in folded and crumbled beds. The quarry is worked intermittently."
"Casey Quarry (formerly the Laurel Creek Quarry); W. W. and J. E. Casey, San Mateo, owners. Located about one eighth of a mile south of Beresford Station, on Laurel Creek. There are two faces; one is a quartz formation, with the quartz considerably fractured and colored in the seams with manganese stains; the other furnishes a red and yellow chert and also a soft, buff-colored sandstone, which has been extensively fractured and crushed. In January, 1905, the county was operating the quarry for macadam for the roadways, using a portable crushing plant consisting of a 15-horsepower gasoline engine on trucks, and a jaw crusher and screen on another pair of trucks. This plant is taken from quarry to quarry as the roads are macadamized in different localities."
Laurel Creek Quarry - See: Laurel Creek (on), San Mateo County, California - Casey Quarry above.
"Vasquez quarry, 1 ½ miles southeast of Miramar, was operated for a short time about 1920, and the product was locally called limestone. The late C. A. Waring (Huguenin, E. 21, p. 179)* made two analyses of this material which are reprinted here. The material is an arkose, consisting of mostly feldspar and calcite."
(* Emil Huguenin and W. O. Castello, "San Mateo County," California Min. Bur. Rept.17, pp. 167-179, 1921)
SiO2, 45.78 percent; 45.63 percent
Al2O3, 11.98 percent; 12.14 percent
Fe2O3, .50 percent; .45 percent
FeO, .10 percent; .05 percent
CaO, 21.27 percent; 21.29 percent
MgO, 1.82 percent, 1.87 percent
Na2O, 2.89 percent; 3.06 percent
K2O, 1.49 percent; 1.35 percent
H2O, 1.40 percent; 1.50 percent
TiO2, .25 percent; .30 percent
P2O5, .14 percent; .13 percent
CO2, 13.02 percent; 12.96 percent
Totals: 100.64 percent; 100.73 percent
Redwood City (2 ½ miles from), San Mateo County, California - the Brittan Ranch Sandstone Quarry (Sandstone) - Excerpt from the Tenth Annual Report of The State Mineralogist For The Year Ending December 1, 1890, California State Mining Bureau, Sacramento: State Printing Office, 1890, pp. 588.
San Mateo County, by W. L. Watts, Field Assistant.
“During the past two years sandstone has been quarried at the Brittan Ranch, about two and one half miles from Redwood City, for use in Redwood and at Wellesley Park; the arch at the latter place, visible from the Southern Pacific Railroad, is said to be built of stone taken from these quarries.”
"Pacific Portland Cement Company, 417 Montgomery Street, San Francisco, erected its Portland cement plant at Redwood City in 1924 and enlarged it in 1927. The plant has a capacity of 6000 barrels of cement a day, and uses the wet process. The company controls 30,000 acres on the floor of south San Francisco Bay on both sides of the channel from Millbrae to Alviso. The accumulation of Recent clam, oyster, and mussel shells found here represents a reserve of tens of millions of tons of good-grade limestone, and the other ingredients for cement are present in the sand and mud of the bay bottom. Suction dredges are used to lift shells and mud to barges alongside, which are then taken to the wharf at the plant where they are unloaded by overhead crane buckets.
"Besides the principal use for making cement, the company also markets 'Empire Brand Agricultural Lime' and limestone for other uses. The cement plant at Cement, Solano County, was closed years ago and the limestone quarry operated so long near Cool, El Dorado County, has not been active since 1940, so that the company's present operations in limestone in California are centered at the Redwood City plant, with smaller-scale operation irregularly at the San Juan Bautista cement plant (formerly Old Mission Portland Cement Company), which has a capacity of 2500 barrels.
"The following are analyses of the shell limestone made by C. H. Newhall. Analyses 1, 2, and 3 are of fresh, clean shells of clams, oysters, and mussels; 4, 5, and 6 are the average, high and low, of old shells, from 10 analyses:
1. (SiO2) 1.08; (Al2O3) 0.93; (Fe2O3) 0.07; (CaCO3) 93.34; (MgCO3) 1.76
2. (SiO2) 0.09; (Al2O3) 0.17; (Fe2O3) 0.38; (CaCO3) 94.01; (MgCO3) 0.23
3. (SiO2) 0.20; (Al2O3) 0.00; (Fe2O3) 0.16; (CaCO3) 95.68; (MgCO3) tr.
4. (SiO2) 0.56; (Al2O3) 0.31; (Fe2O3) 0.19; (CaCO3) 95.34; (MgCO3) tr
5. (SiO2) 0.00; (Al2O3) 0.16; (Fe2O3) 0.18; (CaCO3) 96.69; (MgCO3) tr.
6. (SiO2) 1.16; (Al2O3) 0.78; (Fe2O3) 0.14; (CaCO3) 92.57; (MgCO3) tr.
"Partial analyses of the 'Empire Brand Agricultural Lime' have been made by the State Department of Agriculture showed the following contents of CaCO3: 95.9, 95.7, 94.78, and 94.2 percent. About two-thirds of this material will pass 100-mesh and 93 percent will pass 40-mesh screen, according to an analysis made in 1943."
(Operator) Pacific Portland Cement Co., c/o Ideal Cement Co.; (Address) 821 17th St., Denver 2, Colo.; (Location) Redwood City.
(Operator) California Aggregates (crushed limestone); (Address) 185 Bayshore Blvd., San Francisco; (Location) Rockaway Beach.
"Ken Royce Construction Equipment Company, 185 Bay Shore Boulevard, San Francisco, began work early in 1944 on a deposit of limestone on 190 acres of land in Rancho San Pedro (unsurveyed) just south of the town of Rockaway Beach and on the east side of the Ocean Shore Highway.
"The deposit is part of the Calera (Franciscan) limestone with which more or less chert is associated. It lies on a hill just south of Calera Valley, and was partly covered by soil when work started. The stone is hard, dense, and bluish gray. A quarry was opened and the limestone is being sold as crushed rock for concrete aggregate. The following analysis, reported as made by Abbot A. Hanks, Incorporated, July 10, 1945, has been supplied by the operator."
SiO2, 5.1 percent
Fe2O3, 0.49 percent
Al2O3, 1.05 percent
CaCO3, 91.7 percent
MgCO3, 1.62 percent
Total, 99.96 percent
"Rockaway Quarry, Incorporated, Post Office Box 108, Rockaway Beach, is the present operator of the property known for many years as Rockaway quarry. It adjoins the ocean about 10 miles south of the San Francisco County line and was a source of stone for contractors previous to 1919, when it was closed because of increased freight rates. This company began work in 1942 and has been an important producer of rock used for concrete aggregate and ballast, but so far as known has not sold the stone for its limestone content.
"The deposit is of Franciscan (Jurassic ?) limestone and chert, forming Calera Hill which rises 300 feet above sea-level. The chert occurs as lenses and nodules, and silica has also perhaps infiltrated the limestone. Acceptable limestone might be obtained by selective mining or by crushing and flotation, and apparently some lime was made here many years ago, as Eckel mentioned remains of some old kilns seen there.
"The following analysis of the stone was made by Curtis & Tompkins, Ltd., 236 Front Street, San Francisco, in 1939:"
Insoluble matter (sand, silicates, etc.), 27.65 percent
Soluble iron oxide and alumina, 1.78 percent
Calcium oxide (equivalent to CaCO3=68.47 percent), 38.35 percent
Magnesia (MgO), 0.34 percent
Ignition loss, 31.88 percent
Water soluble alkalinity (as Na2CO3), nil
"San Bruno Quarry, in Visitacion Valley, about 8 miles south of San Francisco, off the San Bruno road. Warren Improvement Company, owners, offices at 230 Montgomery street, San Francisco. There are two adjoining faces. The rock is loaded into boxes on car trucks and hauled 2 miles to the wharf, where the boxes are loaded onto barges and shipped to various points about the bay."
Mine name: Brisbane Quarry; Operator: American Rock & Asphalt, Inc.; Address & County: #1 Old Quarry Rd., Brisbane, CA 94005, San Mateo County; Phone: (415) 467-0720; Latitude: 37.69, Longitude: -122.42, and Mine location number: Map No. 701; Mineral commodity: Stone.
"Daly's Quarry; operated by the United Railroads of San Francisco. On Daly's Hill, San Jose avenue. The rock is a close-grained metamorphosed sandstone, light gray in color, and extensively fractured and seamed. It is crushed by a jaw-crusher at the quarry and loaded directly from bins to electric ballast cars. The entire product is used by the railroad company as crushed rock. About twenty men are employed, and the output averages 80 yards per day."
Mine name: Langley Hill Quarry; Operator: Langley Hill Quarry; Address & County: P. O. Box 620626, Woodside, CA 94062, San Mateo County; Phone: (415) 851-0179; Latitude: 37.37, Longitude: -122.23, and Mine location number: Map No. 702; Mineral commodity: Stone.
“W. O. Tyson, 345 Hilton Street, Redwood City, operates a quarry on the road from Belmont to Half Moon Bay, about 1 mile west of Skyline Boulevard, and just above Crystal Springs Lake.
“The deposit is near a fault and this is probably the reason the limestone mass is found to be broken mostly to about 2-inch and finer sizes, with chert in blocks a foot or more thick.
“A bulldozer is used to remove overburden and to push the rock into a glory hole. A tunnel below caries a belt conveyor, onto which rock is fed. The conveyor delivers to a grizzly through which 2-inch and finer rock drops into bunkers. Coarser pieces rejected by the grizzly are hand sorted, limestone going to a crusher and chert being thrown aside. Trucks load from the bunkers.”
South San Francisco (?), San Mateo County, California - the Crocker-Amazon Quarry
The only information that I have on this quarry is from the excerpt below from the California Guardsman, February 1931. (This may not even be the official name of the quarry or location.) If you have knowledge of this quarry, would you please contact me. Peggy B. Perazzo.
“Northern California marksmanship conference begins with pistol shoot March 8th at 250th Coastal Artillery in San Francisco. New 250th CA pistol range. Drive out Mission Street, south to Lowell Street, turn east on Lowell and follow street and road for about mile to old Crocker-Amazon quarry, adjacent to Mackay Wireless Telegraph Station.”
“Jones Quarry; Fair Estate, San Francisco, owner. On the bay shore, 1 ½ miles east of South San Francisco. The quarry was operated to furnish rubble for the Santa Fe Railroad Company. The rock is handled by three derricks in the face of the quarry and two on the small wharf for loading barges. It varies from a soft, buff-colored sandstone, associated with shale, on the north end of the quarry, to a hard, compact, light gray, metamorphic sandstone on the south end.”