22 



California Division of Mines and Geology 



Bull i97 



other impure carbonate material appear to constitute 

 the bulk of the reserves. 



Other references: Aubury, 1906, p. 66; Huguenin and Costello, 1920, p. 

 51-53, 55; Loizure, 1927, p. 9-12, 15-16. 



McLaughlin lithographic stone deposit. Loca- 

 tion: SW'/,SW'/,(?) sec. .5 5, T. 1 S., R. 2 W., M.D., V/, 

 miles southwest of Danville; Concord I 5-minute quad- 

 rangle. Ownership: R. and A. Mueller, Oakland 

 (1950). 



Hard, locally siliceous limestone occurs as a S-foot 

 bed between sandstone and conglomerate, apparently 

 at the head of Cull Canyon. The bed dips 75° SW and 

 can be traced over a length of 570 feet. It was quarried 

 about 1905 by A. Ramage, who exposed a face 25 feet 

 long by 20 feet high (Huguenin and Costello, 1920, p. 

 23). The stone was tested for lithographic use but was 

 considered unsuitable for that purpose. The deposit 

 may be part of the MulhoUand Formation of Pliocene 

 age (Ham, 1952, p. 15, 22, plate 1). 



Although the McLaughlin body is not shown on 

 Ham's map (1952, plate 1), other small lenses of fine- 

 grained, blue-gray to white, impure limestone of the 

 Orinda-Mulholland unit are indicated in sees. 11 and 

 12, T. 2 S., R. 2 W., and sec. 6, T. 2 S., R. 1 W. Ham 

 also shows a lens of white limestone in SW/ sec. 6 in 

 the Cierbo Formation (Miocene) which he states was 

 tested and found unsuitable for lithographic purposes. 

 Because these limestone lenses are small and impure, 

 their future use would seem to be as local sources of 

 crushed rock. Apparently the blue-gray limestone has 

 been used locally for crushed rock (Ham, 1952, p. 22). 



Ron Hart of Exploration Logging, Inc., (personal 

 communication, 1967) reports that a small lens of 

 limestone 200 feet long by 20 feet thick is exposed near 

 the S'/l cor. sec. 35. This deposit had been recently 

 developed by a small quarry. 



Other references: Laizure, 1929, p. 433-434; Logon, 1947, p. 206. 



Middle Fork deposit. Location: NW'/ sec. 19, T. 

 4 S., R. 5 W. and NE'/ sec. 24, T. 4 S., R. 6 W., M.D., 

 2 miles southeast of Pedro Valley (Pacifica); San 

 Mateo 1 5-minute quadrangle. Ownership: Not deter- 

 mined (1962). 



A fairly large, northwest-trending lens of Francis- 

 can limestone is shown along the Middle Fork of San 

 Pedro Creek by Darrow (1963, plate 1). The mass is 

 shown to be nearly a mile long by an average of 300 

 feet wide in outcrop and to dip 30° to 60° NE. A large 

 tonnage of limestone is indicated by Darrow's map. 

 However, during a brief examination of the north end 

 of the deposit, only scattered limestone outcrops and 

 float were seen over a width of 200 feet. The limestone 

 is typically light and dark gray and contains chert 

 intcrbeds, as well as redistributed silica. 



I he paucity of limestone outcrops may indicate that 

 noncarbonate rocks are extensively associated with 

 the limestone, or it may reflect crushing and fractur- 

 ing becau.se of the proximity of the Pilarcitos fault. 



The deposit is totally undeveloped but warrants suffi- 

 cient prospecting to permit an economic evaluation. If 

 there is any reasonable continuity of limestone 

 between outcrops, accessible reserves for crushed rock 

 uses may amount to several million tons. 



Mission Lime Marl (Gallegos) deposit. Location: 

 SW cor. sec. 31, T. 4 S., R. 1 E., M.D., 2/2 miles east 

 of Irvington and just east of Mission San Jose; Liver- 

 more 1 5-minute quadrangle. Ownership: Gallegos 

 family. State Highway 9, Mission San Jose (1962). 



This is a small surficial deposit of travertine and 

 calcareous tufa that rests on calcareous and fossilifer- 

 ous sandstone of the Briones Formation (Miocene). It 

 is at least 6 to 8 feet thick. The deposit mainly consists 

 of grayish-brown to tan, hard, vuggy, fine-grained 

 travertine and well-bedded, dirty-white to light-tan, 

 porous, soft, impure, calcareous tufa. Travertine out- 

 crops and float are found sporadically over an area 

 about 300 feet in diameter. At the quarry, the tufa 

 generally overlies the travertine and probably is 

 younger. A chemical analysis of the tufa as reported in 

 Laizure (1929, p. 434), showed 83.1% CaCO,. The 

 travertine appears to be considerably purer than that. 



When examined in 1962, the deposit workings con- 

 sisted of an irregular quarry (trench) about 100 feet 

 long by 20 to 30 feet wide (average) by 8 feet deep 

 (maximum) and one or two minor test pits. Small 

 amounts of agricultural limestone (tufa?) were pro- 

 duced around 1924 by Mission Lime Marl Company 

 (Laizure, 1924, p. 184). In 1928, W. S. McLean pro- 

 duced some travertine for terrazzo and other orna- 

 mental uses. Some of the material also may have been 

 used as a source of lime manufactured at Mission San 

 Jose in the nineteenth century (Irelan, 1888, p. 35). 

 There has been no development in recent years. Based 

 on quarry size, total production is probably less than 

 1,000 tons. Carbonate rock reserves are undetermined 

 but small. 



Other reference: Logon, 1947, p. 206. 



Mitchell deposit. Location: SW'/i sec. 32, T. 3 S., 

 R. 4 E., M.D., 1 2 miles east-southeast of Livermore and 

 1 mile south of Corral Hollow; Altamont 7'/2-niinute 

 quadrangle. Ownership: Not determined. 



A.S. Huev ( 1948, p. 62 ) mentions a "lime rock pros- 

 pect . . . developed in Franciscan rocks about a quarter 

 of a mile south of the Tesla fault." The limestone 

 apparently occurs as thin lenses in shale and chert 

 (Huey, p. 18). The deposit lies a quarter of a mile 

 northeast of Mitchell Ravine. 



Oil Canyon (Ilarkinson) deposit. Location: Sees. 

 15 and 16, T. 1 N., R. 1 E., M.D., 5 to 6 miles southwest 

 of Antioch; Antioch South 7'/,-minute quadrangle. 

 Ownership: Not determined. 



A 6-foot-thick ledge of impure limestone in Oil C'an- 

 yon was developed on the land of Colonel Coates prior 

 to 1894, when several tons of rock were shipped to 



