122 
CEMENT MATERIALS AND INDUSTRY. 
[BULL. 
Jackson, A. W. Building stones of California. Seventh Ann. Rep. Cal. State Mj 
eralogist, pp. 206-217. 1888. 
Johnston, W. D. Clays of California. Ninth Ann. Rep. Cal. State Mineralogist, pj 
287-308. 1890. 
Lippincott, J. B. Manufacture of Portland cement in southern California. Water 
Sup. and Irr. Paper No. 60, U. S. Geol. Survey, pp. 135-137. 1902. 
Anon. California cements. Eighth Ann. Rep. Cal. State Mineralogist, pp. S(>5-S84| 
Anon. California cements. Ninth Ann. Rep. Cal. State Mineralogist, pp. 309-3MI 
1S90. 
PORTLAND CEMENT RESOURCES OF COLORADO. 
PORTLAND CEMENT MATERIALS. 
DISTRIBUTION AND COMPOSITION. 
For the purposes of the present bulletin the limestones of Colora 
may be divided, on a geographical basis, into two groups, those lvi 
west of the Front Range, and those lying east of that range in tl 
plains. 
LIMESTONES WEST OP THE FRONT RANGE. 
Of the limestones occurring in centra 1 and western Colorado, we 
of the Front Range, those of Mississippian age seem to be of mo 
promise as Portland-cement materials, though limestones occurring 
other divisions of the Carboniferous, as well as later and earlj 
rocks, are occasionally of value for this purpose. Analyses of 
number of nonmagnesian limestones are given in the following tab! 
Analyses of limestones from Colorado west of the Front Range. 
No. 
1 
2 
3 
4 
5 
(i 
7 
8 
9 
L0 
I I 
L2 
L3 
L4 
Silica 
(Si0 2 ). 
45 
47 
71 
27 
22 
23 
06 
'1-2 
11 
54 
44 
32 
51 
37 
Alumina 
(A1 2 3 ), 
iron oxide 
(FeaOa). 
1. 20 
.77 
. 55 
.14 
Trace. 
.09 
.20 
.10 
.92 
. 13 
.91 
.10 
.19 
Lime 
(CaO). 
40. 64 
46. 65 
47. 40 
53. 7!) 
55. 17 
55. 41) 
55. 81 
55. 45 
55. 68 
50.58 
54. 98 
48. 7:; 
55. 50 
5:;. 64 
Magnesia 
(MgO). 
0.73 
2. 64 
4.49 
.4(1 
.21 
.24 
.24 
Trace. 
. 36 
Trace. 
2.95 
.17 
.73 
( larbqi 
dioxide 
I 
39. 
42. 
42. 
43. 
13, 
43. 
43 
i:; 
10 
n 
41 
i:; 
12 
Ti 
tad 
)i 
nil 
IK 
iei 
ID 
