1978 



Limestone in ihe Coast Ranges 



79 



Ign 

 Sample SiOi FejOj AlsOj CiO MgO PsP, loss 



L&l 5.50% 0.13% 0.20% 51.50% 1.20% 0.01% 41.90% 



L&2 1.50 0.15 0.00 5400 1.30 0.04 42.60 



L&5 1.40 0.J2 0.42 1480 17.20 0.01 45.20 



The above carbonate deposits apparently extend 

 discontinuouslv (•> miles to the southeast to the west 

 flank of Chalk' Peak in S'/^ sec. 28, T. 22 S., R. 5 E. 

 (figure 5). Near the middle of the carbonate belt, 

 where it crosses the connecting road between the 

 coast and Jolon, the limestone masses are too thin and 

 impure to be of commercial interest. Deposits farther 

 to the southeast near Chalk Peak, indicated by Jen- 

 nings (1958), have not been examined. 



The only limestone development in the vicinity 

 took place during the 1880s by the Rockland Lime and 

 Lumber Company, which erected four vertical kilns 

 along the West Pork of Limekiln Creek (SW'X sec. 1 ^, 

 T. 22 S., R. 4 E). Crushed and broken limestone from 

 a large landslide situated on the steep slope northeast 

 of the kilns uas utilized. The company developed sev- 

 eral shallow hillside pits in the crushed limestone and 

 sledded the material down slope to the kilns. The 

 kilns, each of which had a capacity of 110 barrels of 

 lime per day, apparently were loaded overhead and 

 fired by wood. Lime was hauled to Rocklands Landing 

 about a mile away and loaded by aerial tramway 

 aboard waiting ships. Around 1890, the property was 

 acquired and shut down by Henry Cowell Lime and 

 Cement Company. It has been inactive since that time. 



The quarry vicinity was examined briefly by this 

 writer in August 1959. Although good limestone un- 

 doubtedly was selected from the landslide debris for 

 calcining, not all of the limestone is of good quality. 

 Locally, the limestone is dolomitic and associated with 

 metamorphic and granitic rock much like the main 

 deposit higher on the spur. Some of the rocks appear 

 to be in place and either represent Sur Series beds 

 underlying a thin veneer of landslide debris or are 

 portions of a large, partly crushed block that slid 

 downslope from the main limestone mass. It is not 

 likely that further commercial development will take 

 place in this landslide area. 



Other references: ireion, 1888, p 410; Crowford, 1894, p. 392; Crow- 

 ford. 1896, p. 629; Aubury, 1906, p. 72; Logan, 1947, p. 259; Hart, 1966 

 b, p. 63. 



Pacific Carrara Marble Company. A company by 



this name was organized prior to 1880 to develop a 

 deposit of white limestone near (^armel Bav. There is 

 no record of production, but a small deposit of Sur 

 Series limestone near Big Sur is reported (unverified) 

 to be developed by a small, old quarry. 



References: Hanks, 1884, p. 110; logon, 1947, p 260. 



Pico Blanco deposit. Location: Sees. 25 and 36, T. 

 18 S.. and sees. 1, 2, 1 1, and 12, T. 19 S., R. 1 E., M.D., 

 20 miles south of Monterey and 2 to 3 miles northeast 

 of State Highway 1; Big Sur 7'/,-minute quadrangle. 



Ownership: Granite Rock Company, P. O. Box 151, 

 Watsonville, owns sec. 36 and controls adjacent unpat- 

 ented mining claims (1964). 



The Pico Blanco deposit is probably the largest 

 mass of good quality, uniform grade limestone within 

 150 miles of San Francisco. Although reserves appear 

 to be enormous, the deposit has never been developed 

 commercially because of its relatively inaccessible lo- 

 cation and distance from major sources of transporta- 

 tion. 



Formerly, sec. 36 of the deposit was owned by Mrs. 

 C. L. Koch. This section was acquired about 1956 by 

 Tom Maher who also located claims in the vicinity. 

 Maher's holdings were obtained in the late 1950s by 

 Olaf P. Jenkins of Pacific Grove. Jenkins had the 

 deposit sampled and mapped in detail by M. E. Mad- 

 dock (1960, unpublished report) and M. E. Maddock 

 and C. Q. C^arlson (1961, unpublished report). Results 

 of these surveys are summarized by Hart (1966b, p. 

 63-66) and are largely repeated here. Granite Rock 

 Company acquired the Pico Blanco property about 

 1963 after leasing it for a short period of time. 



Ihe name Pico Blanco means "White Peak" in 

 Spanish and refers to the white limestone which caps 

 the summit and east and south flanks of the 3,709-foot 

 peak. The deposit, previously accessible only by foot 

 trails from the Old Coast Road and the Pico Blanco 

 Bov Scout Camp, can now be reached by jeep road, 

 completed in 1964, from the coast via Dani Ridge. 



The deposit contains two bodies of crystalline lime- 

 stone of economic interest — known as the Pico Blanco 

 body and the Hayficld body — and numerous smaller 

 bodies of little commercial importance. The Pico 

 Blanco body is a thick, tabular mass exposed over an 

 irregular area measuring 2'/2 miles from north to south 

 (figure 6). The northern part of the body dips 35° to 

 55° NE and appears to be a homocline; but the south- 

 ern third is structurally complex, probably being a 

 faulted, southeast^ ard plunging anticline. Southwest 

 of the Pico Blanco body is the Hayfield body located 

 in SE'X sec. 1. This mass of crystalline limestone blan- 

 kets the south slope of the peak and probably has a 

 maximum thickness of 100 to 200 feet. 



In large part, the Pico Blanco and Hayfield bodies 

 consist of white or nearly white, coarse-crystalline 

 limestone composed almost entirely of calcite, with 

 minor amounts of quartz and graphite. Local concen- 

 trations of granular quartz in thin resistant bands ex- 

 ist, but they are quantitatively unimportant. Dolomite 

 also is found in some places as alternating bands or 

 disseminated crystals in the limestone. In one place 

 along the South Fork of the Little Sur River, banded 

 dolomite constitutes a horizon 40 to 50 feet thick. 

 Phlogopite (magnesium mica) in small "trains" and 

 other magnesium silicate minerals occur locally. The 

 dolomite, quartz, and silicate minerals present would 

 be considered impurities in most limestone uses, al- 

 though minor occurrences of these contaminants may 

 be diluted by quarrying with high-quality limestone. 



