1978 



Limestone in the Coast Ranges 



87 



This deposit consists of a main body of limestone 

 and several smaller masses lying nearby to the east and 

 to the south (figure 8). The main body is exposed at 

 the summit and south face of Lime Mountain through 

 a relief of 1,000 feet. It is about a mile long in a N 65° 

 W direction, extending from a point just west of the 

 center sec. 15 into the NW'/i sec. 16, and is 1,000 to 

 2,400 feet wide. On the south flank of the mountain in 

 SE'X sec. 16 and the adjacent part of sec. 1 5 is a smaller 

 northwest-trending limestone body roughly 2,000 feet 

 long by a maximum of 900 feet wide. Additional lime- 

 stone outcrops flank the main body to the east and 

 northeast and probably represent two or three sepa- 

 rate small bodies, one being about 50 feet thick near 

 the paved road. The boundaries of the several lime- 

 stone masses are partly obscured by soil and dense 

 vegetation on the north slope of Lime Mountain and 

 by waste dumps at the east end of the main body. 

 According to Taliaferro (1944, figure 9), the lime- 

 stone is part of the \ aqueros Formation (lower Mio- 

 cene), which rests unconformably on Upper 

 Cretaceous sedimentary rocks. The finer grained 

 limestone is virtually identical to the \'aqueros lime- 



stone exposed in the Dubost deposit } miles to the 

 southeast. 



Because bedding features are seldom well defined, 

 the thickness and gross structure of the deposit are 

 difficult to ascertain. The main limestone exposures 

 on the south slope of the mountain appear to be essen- 

 tially a dip slope, although local variations in bedding 

 attitudes, as well 'as brecciation features, suggest that 

 the deposit is disrupted by faulting. As a result, the 

 thickness of the limestone sequence is not known. An 

 estimated minimum thickness of 100 to 200 feet is 

 indicated by the large outcrop area and is partly veri- 

 fied by quarrying which, since 1932, has descended 

 more than 100 feet below the 1947 summit elevation of 

 2,2.30 feet. Additionally, drill holes have penetrated as 

 much as 60 feet of limestone below the present lov^est 

 quarry level, showing an original total of more than 

 160 feet of limestone at the summit (W. J. Smith, 1962, 

 personal communication). 



Several grades and types of limestone are found in 

 the deposit, but the ratios and stratigraphic relation- 

 ships of the various types are not known. The 

 predominant limestone in the quarry area is light- 





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Photo 15. Looking west at main quarry of Lime Mountain limestone deposit, August 1968. Quorry, situated at summit of lime Mountoir 

 of lime-grade limestone in Coast Ronges and is used for beet-sugor manufacture. Photo courtesy of W. J. Smith of Baton and Smith. 



is principal source 



