1978 



Limestone in the Coast Ranges 



13 



of Fort Ross; Plantation T'/j-minute quadrangle. Own- 

 ership: Not determined. 



"Extensive deposit.s of pulverulent limestone" were 

 noted hv Watts (IS'P', p. 463) in (Coleman Gulch. Lo- 

 gan (1947, p. }}-\) corrected the spelling of "Coleman" 

 to "Kohlman" and stated that "only meager evidence 

 of limestone was found." Current topographic maps 

 now show the name of the stream to be Kolmer Gulch. 

 There is no development of the deposit. 



Ofher reference: Honke ond Ver Planck. 1950, p. 95. 



Pioneer Shell Company. The company operates a 

 plant at 100 East "D" Street, Petaluma, where oyster 

 shells from San Erancisco Bay are processed. (Eor 

 description see San Erancisco Bay Shell deposits, San 

 Erancisco Bay district.) 



Pope Valley deposit. Location: \'icinity of sec. 

 32(?), T. 10 \., R. .> VV., M.D., about 11 miles north 

 of St. Helena; St. Helena 15-minute quadrangle. Own- 

 ership: Not determined. 



According to Crawford (1896, p. 629), lime was 

 made in two kilns in Pope \'alley during the 1890s. 

 Reportedly, only small quantities of lime were made 

 although "two kilns are in constant use". The source 

 of limestone is not known but could have been thin 

 beds or lenses of limestone that commonly occur in 

 the Knoxville Eormation or overlying Lower Creta- 

 ceous rocks of Pope \'alley. An old lime kiln in or near 

 sec. 32 (Dow and Thayer, 1946, p. 23) may relate to 

 the above. Kno.wille and associated strata are exposed 

 along the north margin of Pope N'alley and near sec. 

 32. 



Other reference: Bradley, 1916, p. 271. 



Purviance Ranch deposit. Location: Possibly sec. 

 23 or 24, T. 9 N., R. 10 W., M.D.; Healdsburg 15- 

 minute quadrangle. Ownership: Not determined. 



Small outcrops of limestone have been reported 3/2 

 miles west of Healdsburg on the Purviance Ranch. 

 Apparently there is no development of this deposit, 

 although C. A. Perry had an option on it (Laizure, 

 1926, p. 3 36). The deposit was not located during the 

 present study. A chemical analysis of the limestone, 

 made in 1906 bv Thomas Price and Son, is partially as 

 follows: 93.45% CaCOj, 1.22% MgCO,. l.l'3% 

 FeCOj, 1.96% AI2O3, and 1.59% SiOj. The limestone 

 lies in an area underlain by the Eranciscan Eormation. 



Other references: Logan, 1947, p. 334; Honke and Ver Planck, 1950, p. 

 95. 



Unnamed deposit (near Geyserville). Location: 

 Near E'; cor. sec. 14, I . 10 \., R. 9 \V., M.D., 4'/, miles 

 east of Gcvserville; Healdsburg 15-minute quadran- 

 gle. Ownership: Not determined. 



This deposit is developed near an old marble quarry 

 and kiln. It is described by Gealey (1951, p. 46, plate 

 1): "The marble is gray and finely crystalline, but in 

 scattered patches some calcite crystals reach a length 

 of as much as 2 inches. The material is in metamor- 

 phosed Eranciscan limestone. Lime was first burned 



here about 1880. The body is far too small to be of 

 economic importance today." The deposit may be the 

 same one referred to by Irelan ( 1888, p. 633) or Craw- 

 ford (1894, p. 396). 



NORTH BAY DISTRICT (B-2) 



This district includes all of the deposits in Marin 

 and Solano Counties and one deposit in southern 

 Napa Countv (plate IB). Not only have these deposits 

 contributed substantially to the early economy of the 

 San Erancisco Bay area, they have also contributed 

 richlv to its history. Possibly the first limes'one depos- 

 it worked commercially in the Coast Ranges of C.ali- 

 fornia is the tiny Olema deposit, operated about 

 1850-1852. 'Ihe Inverness Park and Cement Hill 

 deposits also were verv early sources of lime rock. 

 About 1860, California's first hydraulic cement plant 

 was established at Benicia. It used shells or impure 

 limestone from local deposits until it was shut down 

 around 1890. One of the earliest Portland cement 

 plants in (>alifornia was established at the (dement 

 Hill deposit in 1902. Here, travertine was quarried as 

 the principal raw material. The next year, impure 

 shelly limestone was developed as a source of cement 

 rock at the Napa Junction deposits. Some of these 

 deposits, along with the Tolenas Springs deposit, also 

 vielded limestone for terrazzo, decorative stone, and 

 flux. 



Only the Tolenas Springs deposit is now active. It 

 presently is operated on a small scale, yielding traver- 

 tine and onyx marble for terrazzo. 



The deposits are geologically varied, consisting of 

 crystalline limestone of pre-Cretaceous age, dense 

 limestone of the Eranciscan Eormation, impure lime- 

 stone (both fine grained and bioclastic) of late Meso- 

 zoic and early Tertiary age, and shell and surficial 

 carbonate deposits of C^aternary age. 



The deposits of the North Bay district seem to offer 

 little significant C(jmmcrcial potential, except for 

 deposits useful as a source of decorative and crushed 

 rock. Late Quaternary shell accumulations, such as 

 that found in Tomales Bay (see Eomales Bay shell 

 deposit) mav provide additional economic possibili- 

 ties. 



Bender deposit. Location: .Approx. sec 21, T. 3 

 N., R. 9 \V. (proj.), VI. D., 1 mile south-southeast of 

 Inverness, Marin C'ounty; Point Reyes 15-minute 

 quadrangle. Ownership: E. A. Bender, Inverness 

 (1962). 



Several small bodies of crystalline limestone as- 

 sociated with biotite schist and intruded by quartz 

 diorite are reported bv the owner to occur in a small 

 canyon that drains the northeast flank of Point Reyes 

 Hill. The limestone is situated '/j to % of a mile inland 

 from W'illou Point on Tomales Bay. It is similar to the 

 metamorphosed Sur Series limestone of the southern 

 (^oast Ranges, being coarse crystalline, \\hite, and 

 sparsel}- flecked v^•ith graphite flakes. Scheelite crys- 

 tals up to half an inch occur in the limestone, \\ hich 



