California Division of Mines and Geology 



Bull. i97 



Limestone of the Franciscan Formation is exposed 

 as a series of outcrops along a low hill a few hundred 

 feet east of U.S. Highway 101. As indicated by e.xpo- 

 sures and limestone float, the deposit extends over a 

 length of about 600 feet and a maximum width of 100 

 feet. The deposit consists of a sequence of well-bed- 

 ded, massive limestone interleaved with thin chert 

 beds and lenses. Consistent bedding exposures show 

 the deposit to strike N 10° E and dip 70 to 80° E. 

 Limestone along the west side of the deposit is typical- 

 ly rust red to reddish brown, dense, fine grained, 

 foraminiferal, and cut by numerous veinlets of calcite. 

 This part of the sequence grades easterly into yellow- 

 ish-gray, red-mottled limestone of otherwise similar 

 character. Both types of limestone appear to be high 

 in calcium, the only visible impurities being iron ox- 

 ide in the red'varieties and discrete shert beds. Similar 

 but smaller limestone deposits are exposed in road 

 cuts to the south, three-quarters of a mile north of 

 Laytonville. 



A chemical analysis of the Fisher Ranch limestone 

 is reported to be 93.16% CaCO,, 0.39% MgCO,, 0.69% 

 Fe,0, and Al^O,, and .S..S6% insoluble (Logan, 1947, 

 p. 2.^4). Two additional analyses of the yellowish (FR- 

 1) and reddish (FR-2) limestone were made by Matti 

 Tavela and Lydia Lofgren from samples collected by 

 this writer in 1963: 



Ign 

 Simple SiO, AW, Fe,0, MgO CM K,0 P.O, loss 



FR-1 2.5% 0.07% 0.30% 0.38% 53.2% 0.00% 0.08% 43.2% 



FR-2 1.0 0.00 0.43 0.84 53.8 0.00 0.07 43.6 



There has been no development of the deposit, and 

 the limestone would have to be beneficiated for most 

 limestone uses. However, the limestone shows rather 

 striking colors and may be useful as a source of colored 

 granules or as a decorative material. The deposit is 

 readily accessible, but it is about 13 miles from the 

 nearest rail facility at Longvale. Reserves of limestone 

 are estimated to be 300,000 tons per 100 feet of depth. 

 Because of a maximum relief of approximately ."iO feet, 

 reserves above local base level are relatively small. 



Other references: O'Brien, 1953, p. 361; Irwin, 1960, p. 35, 43; Boiley ond 

 others, 1964, p. 75. 



Quinan Ranch deposit. Location: Sec. 26, T. 17 

 N., R. 1 3 W., M.D., 2 miles northwest of Laughlin and 

 10 miles north-northwest of Ukiah; Willits l.')-minute 

 quadrangle. Ownership: Grace T. Post (1953). 



This surficial deposit has been described by Logan 

 ( 1947, p. 2.'>4) as terraces of travertine and calcareous 

 tufa formed from spring action near the top of a ridge. 

 The springs issue along a fault that strikes west and 

 dips 61° S. One terrace, at an elevation of 2,000 feet, is 

 250 feet long by 100 feet wide. To the east and 35 feet 

 below the first terrace, a lower terrace covers an acre 

 or less in area. This is developed by a pit 27-by-50 feet 

 with a depth of lO-to-15 feet. A 6- to H-foot thick bed 

 of travertine, underlain by soil and angular rock frag- 

 ments, is exposed here. A chemical analysis made of 



the travertine shows 94.97% CaCO,, 1.51% MgCO,, 

 0.24% FczO, and AijO,, and 3.20% insoluble (Logan, 

 1947, p. 254). 



Northwest Pacific Lime and Sulphur Company 

 worked the deposit from 1930 to 1933. Based on the 

 size of the pit and the thickness of the deposit, produc- 

 tion must have been in the order of 700 tons. The 

 carbonate material was trucked a few miles to a mill 

 at Laughlin on the Northwestern Pacific Railroad. 

 Here, the material was crushed and pulverized for use 

 as a soil conditioner. 



Other references: Averill, 1929, p. 462; O'Brien, 1953, p. 361. 



Usal deposits. Location: Sees. 1 and 2, T. 23 N., R. 

 18 W., and sees. 26, 35, and 36, T. 24 N., R. 18 W., M.D., 

 16 miles south of Garberville; Piercy 15-minute quad- 

 rangle. Ownership: Not determined. 



About 30 small lenses of limestone comprising two 

 northwest-trending belts are mentioned in a report on 

 manganese by Trask et al. (1950, p. 146-147). The 

 limestone is light gray and fine grained, except near 

 the manganese ore, where the color is pinkish. Most of 

 the limestone lenses are less than 5 feet thick and 20 

 feet long, although one is 50 feet thick by 1 50 feet long. 

 The limestone is reported to be similar to the lime- 

 stone near Laytonville (Irwin, 1960, p. 43). 



The limestone has never been used, and future de- 

 velopment is limited by the size of the lenses and the 

 remoteness of the area. However, other limestone 

 deposits may exist nearby. 



CLEAR LAKE DISTRICT (A-3) 



Deposits of the Clear Lake district lie in Glenn, 

 Colusa, Lake, and Yolo Counties (plate lA). Small 

 amounts of limestone were produced many years ago 

 at the Manzanita and Wide Awake deposits, apparent- 

 ly for use in retorting mercury ore from the mines 

 near Wilbur Springs. A little limestone was also quar- 

 ried in Burns \'alley as a source of lime in the late 

 nineteenth century. None of the deposits appears to 

 be of significant commercial value although some in- 

 terest has been shown recently in the surficial deposits 

 near Wilbur Springs as sources of decorative stone. 



In addition to the deposits described below, lime- 

 stone has been reported from sec. 19, T. 1 1 N., R. 7 W., 

 M.D., where the Knoxville Formation is exposed. 

 That same formation also is found in sec. 36, T. 1 3 N., 

 R. 6 W., where the remains of an old lime kiln are 

 reported (Logan, 1947, p. 248). 



Surficial deposits of notable size have been de- 

 scribed by Waring (1915, p. 183-184, 193-194, 196- 

 198) at Highland, Dinsmore, Hough, and Grizzly 

 Springs. A small, undeveloped deposit of onyx marble 

 lies near HullviUe in sec. 12, T. 18 N., R. lO'W., ,M.D., 

 (Bradley, 1916, p. 225). 



Burns Valley deposit. Location: T. 1 3 N., R. 7 W., 

 M.D., near C-lear Lake Highlands; Lower Lake 15- 

 minute quadrangle. Ownership: Not determined. 



