42 



California Division of Mines and Geology 



Bull 197 



The various raw materials are further crushed, 

 ground, beneficiated, and blended to make up the raw 

 feed (slurry). The feed is processed wet in six kilns, 

 ranging from 444 feet to 454 feet long, to obtain the 

 clinker. This is later ground with gypsum from Mex- 

 ico to produce a variety of cement products. In addi- 

 tion to cement, the operator has produced crushed 

 rock for use in concrete aggregate and road construc- 

 tion for many years. Such material has come from 

 overburden and low-grade limestone. A sand by-prod- 

 uct, derived as tailings from the flotation circuit, also 

 is recovered for commercial sales ( Kleiber and Meisel, 

 1964, p. 44). 



Total production of limestone and associated chert 

 at the Permanente deposit is estimated to be on the 

 order of 40 million tons. Proved and estimated reserve 

 figures are not available, but deep diamond-drilling 

 indicates that reserves considerably exceed past pro- 

 duction. 



Other references: Franke, 1930, p. 9; Krivari, 1942, p. 374-397; Logon, 

 1947, p. 313-317; Dovis and Jennings, 1954, p. 355-358, 361, 364-366; 

 Bowen and Gray, 1962, pt. 2, p. 4; Bailey and Everhort, 1964, p. 24. 



San Jose Cement (Guadalupe Portland Cement) 

 Company formerly owned a "deposit of .?31 acres of 

 undeveloped limestone" in sees. 4 and .5, T. 9 S., 

 R. 1 E., and sec. .32, T. 8 S., R. 1 E., M.D. (Franke, 

 1930, p. 9-10). This property probably included the 

 Guadalupe Reservoir deposit (which see). The com- 

 pany lapsed as a corporation in 1936 (Logan, 1947, p. 

 313). 



Snell Ranch deposit. Location: Z'/jNE'X sec. 28, T. 

 8 S., R. 1 W., M.D., 1 mile southeast of downtown Los 

 Gatos; Los Gates 15-minute quadrangle. Ownership: 

 J. A. Snell, Foster Road, Los Gatos (1962). 



1 his deposit of Franciscan limestone is shown by 

 Bailey and Everhart (1964, plate 1) to be an east-west 

 lens 1,300 feet long by a maximum of 200 feet wide. 

 Where exposed along Foster Road, the deposit is at 

 least 25 to 30 feet thick and dips gently to moderately 

 south. It is composed mainly of dark, fine-crystalline, 

 somewhat mottled, bituminous, thinly bedded lime- 

 stone that appears to be brecciated and recemented 

 with calcite. A chemical analysis by Matti Tavela in 

 1963 of typical limestone from the quarry showed 

 1.3% SiO',, 0.60% AI2O3, 0.37% FeaOa, 0.35% MgO, 

 53.9% CaO, 0.10% P205and 42.8% ignition loss. Light 

 dove-gray, fine-grained limestone is present in lesser 

 amounts. Thin interbeds of dark chert constitute the 

 main visible impurity. 



Ihe deposit was developed by a tiny quarry west of 

 the road, from which less than 1,000 tons of material 

 was excavated. The date or purpose of development is 

 unknown, although it is possible that this limestone 

 was used by Los Gatos Lime Company (which see). 



Wright's Ranch deposit. Location: probably sec. 

 16 (proj.), T. 9 S., R. 2 E., M.D., 5 miles southeast of 

 New Almaden mine; Los Gatos 15-minute quadran- 

 gle. Ownership: Not determined. 



"A large and valuable deposit of marble" is de- 

 scribed by Crawford ( 1894, p. 394). It is exposed con- 

 tinuously over an area 60 feet to more than 100 feet 

 wide and more than 3,000 feet long. The limestone is 

 usually light gray but occasionally is tinged with red 

 or brown. Some is nearly white, "but it is mostly 

 mottled or curiously marked by blotches and streaks 

 of light shades in the darker crystalline ground-mass." 

 Crawford indicates the deposit to be of limited devel- 

 opment, although some stone apparently was quar- 

 ried. 



This deposit probably is included in the mile-long, 

 northwest-trending group of limestone lenses mapped 

 as part of the Franciscan Group by Bailey and Ever- 

 hart (1964, plate 1) in sec. 16 (proj.), by T. 9 S., R. 2 

 E. The largest of these lenses is shown to be a thin, 

 sinuous body less than 100 feet thick, 1,200 feet long, 

 and dipping steeply to the southwest. 



Other reference: Logon, 1947, p. 317. 



Unnamed deposits (near Chesbro Reservoir). 



Location: Approx. sec. 23 (proj.), T. 9 S., R. 2 E., 

 M.D., north of Chesbro Reservoir and 3 miles west of 

 Morgan Hill; Morgan Hill 15-minute quadrangle. 

 Ownership: Not determined. 



Bailey and Everhart (1964, p. 21) mention the oc- 

 currence of limestone in the Franciscan Formation 2 

 miles south of the mouth of San Bruno Canyon. By 

 way of comparison, they state that the "limestone 

 crops out in more continuous exposures" than in the 

 adjacent Santa Teresa Hills quadrangle to the west 

 (see Bailey and Everhart, 1964, plate 1). Some lime- 

 stone (possibly the same as above) also is reported 

 along Llagas Creek in the Morgan Hill quadrangle 

 (Bailey, Irwin, and Jones, 1964, photo 33). Neither of 

 these deposits was examined by this writer. 



SANTA CRUZ DISTRICT (B-5) 



The Santa Cruz district covers those deposits in the 

 Ben Lomond Mountain-Santa Cruz area of Santa Cruz 

 County. Limestone has been produced continuously 

 in this district since 1851, when Davis and Jordan first 

 established a quarry and lime kiln near Santa Cruz. 

 Although accurate records are not available, total 

 limestone production is estimated to be close to 30 

 million tons. The San \'icente deposit of Pacific Ce- 

 ment and Aggregates, Inc., yielded about 25 million 

 tons of limestone, most of which went into the manu- 

 facture of cement. It is estimated that 3 or 4 million 

 tons of lime rock were calcined from 1851 to 1947. 

 Crushed limestone for livestock feed, agricultural use, 

 riprap, and other purposes also was produced in sub- 

 stantial amounts. 



With one possible minor exception (see Wagner's 

 Park deposit) , all of the limestone is recrystallized and 

 occurs as massive beds associated with schist and other 

 metamorphic rocks which are commonly correlated 

 with the pre-Oetaceous metamorphic Sur Series of 

 the Santa Lucia Range in Monterey County. Granitic 



