"Exclusive of San Francisco County, Marin is the smallest county in California, having a land area of only 529 square miles. The Pacific Ocean is its western boundary, Sonoma County on the north and east, San Pablo and San Francisco bays on the east, with the latter and Golden Gate on the south. Its topography is quite rugged and picturesque, with occasional small and fertile valleys. Its most prominent topographic feature is Mount Tamalpais which overlooks both bay and ocean region from an elevation of 2600 feet. Other notable features are Tomales, Drakes, Bodega and Bolinas bays, on the ocean side, and Richard's Bay on the inland side. Angel and Belvedere islands are included in Marin County. The areas around San Rafael, Mill Valley, Sausalito, and intermediate points are popular suburban residence sections.
"The mineral resources of Marin County, while limited numerically, are none the less important individually. They are mainly structural and industrial materials. In the order of their production to date they are: brick, stone industry, mineral water, granite, salt, and copper. Their total recorded output is $3,869,799 to the end of 1913.
"In addition to the above, occurrences have been noted as asphaltum and petroleum, chrome, coal, jasper, garnets, manganese, and natural gas. Attempts have been made to exploit some of these, but without commercial success so far."
The following information is taken from the table on page 243 entitled, "Marin County - Table of Mineral Production."
Granite Production in Marin County (listed in the Miscellaneous and unapportioned" section.)
1895: 7,000 cubic feet granite; Value: $5,000.
Stone Industry Production in Marin County (stone only):
1894: Value: $16,850.
1895: Value: $7,790.
1896: Value: 7,849 tons; Value: $8,260.
1897: 6,000 tons; Value: $7,200.
1898: 1,710 tons; Value: $1,800.
1899: 4,400 tons; Value: $5,150.
1900: 3,000 tons; Value: $2,500.
1901: 34,000 tons; Value: $27,987.
1902: 149,450 tons; Value: $105,350.
1903: 144,715 tons; Value: $140,332.
1904: 216,576 tons; Value: $170,995.
1905: 113,000 tons; Value: $44,250.
1906: 54,000 tons; Value: $53,000.
1907: 157,100 tons; Value: $134,111.
1908: 111,686 tons; Value: $66,700.
1909: 132,010 tons; Value: $100,000.
1910: 112,000 tons; Value: $74,700.
1911: 173,646 tons; Value: $108,786.
1912: 5,300 tons; Value: $3,000.
1913: 428,357 tons; Value: $198,953.
Totals: 1,854,799 tons; Value: $1,244,724.
Area: 529 square miles.
Population: 27,342 (1920 census)
Location: Adjoins San Francisco on the north.
"Mineral production in Marin County during the year 1919 reached a value of $228,974, as compared to the 1918 output, worth $176,183, the increase being due to crushed rock, and brick. This county is not especially prolific in minerals, although among its resources along these lines are brick, gems, manganese, mineral water, soapstone, and miscellaneous stone.
"In thirty-seventh place, commercial production for 1919 was:"
(Headings for the information below are: Substance, Amount, and Value.)
Stone, miscellaneous, ---, $127,111
Other minerals,* ---, $101,863
(Total value) $228,974
(* Includes brick and mineral water.)
"There was some early-day production of lime in Marin County, but limestone has not been produced for 50 years, and is not generally listed among the mineral resources of Marin County. Nevertheless, an important deposit of Gavilan (Paleozoic ?) limestone occurs at the head of Tomales Bay, and a deposit of Calera (Franciscan) limestone has been noted south of Olema on the road to Bolinas. Both were described by Edwin C. Eckel (33, pp. 353, 356).* They are called here for convenience Tomales Bay deposit and Olema deposit...."
(* "Limestone Deposits of the San Francisco Region," California Div. Mines Rept. 29, by Edwin C. Eckel, 1933, pp. 348-361.)