44 



California Division of Mines and Geology 



Bull. 197 



extensively, but it is not known when they were devel- 

 oped. The Cowell Lime and Cement Company ceased 

 operating about 1947. Prior to that, the Cowell Home 

 Ranch deposits had been utilized as a source of lime 

 rock continuously for 96 years, with the possible ex- 

 ception of a few years prior to 1900. The only produc- 

 tion in recent years was in 1956 and 1957 when 

 Granite Rock Company produced a large amount 

 (200,000 tons reportedly) of limestone for riprap from 

 the quarry located in W'/ cor. sec. 11. 



The Home Ranch deposits consist of numerous 

 small to moderately large bodies of crystalline lime- 

 stone associated with schist and other metamorphic 

 rocks similar to the Sur Series of the northern Santa 

 Lucia Range. Locally, the metamorphic rocks are cut 

 by granitic rocks of Cretaceous age. Although bedding 

 features are generally obscure, wide variations in bed- 

 ding attitudes as well as common breccia features indi- 

 cate the limestone masses to be considerably disrupted 

 by faulting. Young sedimentary strata and heavy soil 

 cover the limestone in many areas, making it difficult 



to ascertain the extent of the various deposits; some of 

 the limestone bodies may be larger than indicated on 

 the accompanying map (figure 4). The limestone 

 ranges from fine to very coarse crystalline and from 

 nearly white to gray and blue gray, sometimes being 

 banded or mottled. In many places, schist or quartzitic 

 rocks are interlayered with the limestone; and, locally, 

 granitic dikes and quartz veins cut the limestone. 

 Aside from the noncarbonate rocks associated with 

 the deposits, the main impurities in the limestone ap- 

 pear to be silica and silicate minerals. Dolomite rock 

 was not identified in these deposits but may be present 

 locally. Results of chemical analyses are presented in 

 table 9. Other analyses are given in Eckel (1933, p. 

 353). 



The several deposits and quarries that lie on the 

 Cowell Home Ranch were examined briefly by this 

 writer in July and August 1963. They are described 

 below by letter designation (A, B, C, D, E, F), the 

 letters corresponding to those shown on the map (fig- 

 ure 4). 



Figure 4. Mop of limestone deposits near Santo Cruz. 



