118 
CEMENT MATERIALS AND INDUSTRY. 
SAN BENITO COUNTY. 
[BULL. 24J !Ci 
The following" partial analyses of very pure limestones occurrirJ 
west of Hollister, in San Benito County, are given in the Mineral 
Resources of the United States for 1889-90, page 383: 
Analyses of limestones from San Benito County, Cal. 
Silica (Si0 2 ) 
Lime carbonate (CaC0 3 ) 
2.10 
96.00 
0.7 
99.2 
0. 
99. 
SANTA CHUZ REGION. 
Extensive deposits of a soft, chalk-like limestone occur near 
Cruz. These deposits are accompanied by shales and clays of 
composition, as can be seen from the following analyses: a 
Analyses of cement materials from Santa Cruz, Cal. 
Sani 
goo 
"■'■ 
V 
Limestone. 
Silica (Si0 2 ) 2.40 
Alumina (A1 2 3 ) .51 
Iron oxide (Fe 2 ;5 ) 56 
Lime (CaO) 51.31 
Magnesia (MgO) | 1. 25 
Alkalies (K 2 0, Na 2 0) 1. 45 
Carbon dioxide ( C0 2 ) 40. 32 
Water 1 . 21 
4.71 
1.20 
.60 
50. 02 
.75 
1.80 
39. 25 
1.40 
Clay. 
63.73 
22.12 
9.01 
2.83 
Trace. 
.21 
n. d. 
1.12 
60.03 
21.76 
11.49 
3. 37 
.25 
1.36 
n.d. 
1.45 
62 
20. If 1 
s - 1 m 
M M 
Trad 
"Eighth Ann. Rept. California State Mineralogist, p. 881. 
SOLANO AND CONTRA COSTA COUNTIES. 
Beds of soft limestone, usually quite high in clayey matter, ai 
exposed from Vallejo to Goodyears, Solano County, and from ' Mourn 
Diablo to Pinole, Contra Costa County. 
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