1978 



Limestone in the Coast Ranges 



71 



stone is medium to coarse crystalline and light blue 

 gray, but some is locally siliceous and dolomitic. The 

 great majority of carbonate bodies in the northeastern 

 two-thirds of the group are small and scattered (the 

 southwestern end of the Power Line group was not 

 examined). Although limestone reserves mav amount 

 to several million tons or more, the deposits have not 

 been sampled or carefully examined, and little can be 

 said of the chemistry of the deposits. 



Quail Creek deposit. Location: N'/j sec. 7, T. 1 5 S., 

 R. 5 E., M.D., 6 miles northeast of Chualar; Gonzales 

 15-minute quadrangle. Ownership: Hazel Hurt, Sali- 

 nas (I960). 



At the west end of the Quail Creek deposit, adjacent 

 to (^ail Creek, a series of small quarries was worked 

 as a source of limestone for lime in the early 1900s. It 

 is quite possible that these quarries were operated by 

 J. C. Jens, who reportedly produced limestone from 

 near Chualar from 1910 to 1913 (unpublished 

 records), or by Spreckels Sugar Company, which op- 

 erated in the vicinity prior to 1910 (Laizure, 1925, p. 

 43). .ApparentI}-, the deposit then lay idle until 1959, 

 when Barnes (construction Company of San Marino 

 developed a large quarry on the south slope of the 

 ridge just east of the first development. In April 1960, 

 this operation was inactive, although stockpiles and 

 equipment remained at the quarry (Hart, 1966b, p. 

 60). 



This deposit consists of several narrow lenses or 

 beds of carbonate rock that extend nearly a mile east- 

 ward from Quail Creek and dip 30° to 50° S. The beds 

 are interleaved locally with schist, and the whole has 

 been penetrated by granitic dikes and sills. The main 

 lens attains an estimated maximum thickness of 150 

 feet, including schist and granitic salients, but is much 

 thinner at its extremities. Because the carbonate beds 

 dip more or less parallel to the southwest slope of the 

 ridge, the deposit appears to be much larger than it 

 actually is. It consists of nearly white, fine- and coarse- 

 crystalline calcite and medium-crystalline dolomite, 

 which occur together in varying proportions to form 

 limestone, dolomitic limestone, and dolomite. Accord- 

 ing to Bowen and Gray (1959, p. 37), the western 

 third of the deposit consists of mixed carbonate rock 

 but the eastern two-thirds appears to be mainly lime- 

 stone. 



Barnes Construction C^ompany first developed the 

 deposit in early 1959 by stripping the soil and caliche 

 cover and by trenching and drilling, reportedly block- 

 ing out 2 million tons of rock. This was followed by 

 quarrying later in 1959 and possibly in early 1960. The 

 quarry, which is more than 1,000 feet long and has an 

 estimated maximum relief of 150 feet, is located in the 

 western half of the deposit. 'I"he face, which probably 

 slopes an average of 40°, is irregularly benched. By 

 means of cut and fill, the quarry floor has been extend- 

 ed 200 to 300 feet out from the toe of the face. Al- 

 though the quarry was not active when visited in 



April 1960, the limestone apparently had been quar- 

 ried somewhat selectively and transported to a bench 

 about 20 feet above the quarry floor. By passing the 

 broken rock over a grizzly or grate on an inclined 

 chute from the bench to the quarry floor, some of the 

 decomposed granitic and other deleterious fines were 

 removed. The material was subsequently crushed and 

 screened with portable equipment, stored in open 

 piles, and sacked for shipment. In April 1960, there 

 were six conical piles of crushed rock ranging from 10 

 to 20 feet high and containing rock ranging from plus 

 6-inch to minus '/^-inch fines. In addition, several thou- 

 sand sacks of roofing granules C/e by '/g inch) and 

 landscape rock (/^ by /g inch) were stacked on pallets, 

 and several pieces of portable equipment (scraper, 

 loader, fork-lift, conveyor, and sacking machine) re- 

 mained at the quarry. 



Based on observations at the quarry, production 

 would appear to be fairly large. However, much of the 

 material apparently was used to construct a road to 

 the quarry. Unpublished records show that only a 

 modest amount of carbonate rock was sold for land- 

 scape and roofing purposes. 



Reserves of the Quail Creek deposit are difficult to 

 estimate because the dimensions of the carbonate bod- 

 ies are not sufficiently known. Perhaps several million 

 tons of carbonate rock could be quarried here; but the 

 proportion, quantity, and quality of limestone and 

 dolomite available are undetermined. A chemical anal- 

 ysis of a grab sample taken from one of the stockpiles 

 suggests that dolomite predominates in the quarry 

 area. The analysis, made by Lydia Lofgren of the Divi- 

 sion of Mines and Geology in 1962, showed 17% MgO, 

 36.25% CaO, 2.4% Fe^O,', and 0.42% SiO^. Although 

 heterogeneous in composition and color (some iron- 

 staining), most of the carbonate rock is physically 

 sound and probably suited to various construction, 

 roofing, and landscaping uses. 



Reeves Northeast deposits. Location: Sec. 4, T. 14 

 S., R. 5 E., M.D., 7'/2 miles .south of Hollister; Gonzales 

 15-minute quadrangle. Ownership: Dr. Rollin Reeves, 

 Salinas (1964). 



A number of small to medium-sized masses of lime- 

 stone and dolomite lie along the northeast-trending 

 ridge in the east or northeast part of the Reeves Ranch. 

 Two of the better quality limestone deposits lie at the 

 ridge crest close to the corner common to the Martin, 

 Kaiser-Harris, and McCray (Reeves) properties. The 

 largest and most northeasterly deposit, which lies 

 partly on the .Martin and McCray Ranches, is roughly 

 1200 feet long by 700 feet wide. It consists of blue- 

 gray, medium-crystalline, banded limestone that 

 weathers into platy fragments. An analysis of a typical 

 sample showed 52.67% CaO, 1.41% Mg'O, 1.56% SiO^, 

 0.17%) Fe,0,, 0.95%) AI^O,, and 0.03%) P^O, (Bowen 

 and Gray, 1959, p. 36). 



Judging from the outcrops, the deposit appears to be 

 gently dipping and probably contains less than I mil- 



