134 
CEMENT MATERIALS AND INDUSTRY. [bull. 24^ 
Analyses of Mississippian limestones from Illinois. 
Silica (Si0 2 ) 
Alumina (A1 2 3 ) 
Iron oxide ( Fe 2 3 ) 
Lime carbonate (CaCO :i ) 
Magnesium carbonate (MgC0 3 ) 
0.05 
.20 
94.68 
4.31 
2 
3 
4 
0.37 
2.72 
12.50 
.27 
1. 06 
2.10 
92.77 
90. 86 
82.48 
6.75 
3.18 
0. I 
2. IS 
95. 65 
.81 
1. Quiney, Adams County. H. Pratten, analyst. Geology of Illinois, vol. 1, p. 108. 
2. Quiney, Adams County. C. G. Hopkins, analyst. Twentieth Ann. Kept. U. S. Geol. Survey 
pt. 6, p. 377. 
3. Rosielare, Hardin County. H. Pratten, analyst. Geology of Illinois, vol. 1, p. 374. 
4. Nauvoo, Haneock County. H. Pratten, analyst. Ibid., p. 99. 
5. Marblehead, Adams County. N. G. Bartlett, analyst. Twentieth Ann. Rept. U. S. Geol. Survey I 
pt. G, p. 377. 
PENNSYLVANIA (" COAL MEASURES") LIMESTONES. 
DISTRIBUTION. 
The Pennsylvania ( u Coal Measures,") rocks of Illinois cover most o [ 
the State south of a line drawn through Paxton, Wilmington, Lasalle 
Princeton, and Rock Island. The greater part of this thick series o 
Coal Measure rocks consists of shales and sandstones, but the presence 
of occasional relatively thin beds of limestone is of interest, for it i 
from these limestone beds of the Coal Measures that three of the four 
Portland-cement plants now operating in Illinois draw their supply o 
raw material. 
The limestones occurring in the Coal Measures of Illinois are usual! 
thin, but fairly persistent. One thick bed, or series of beds, is well 
exposed near Lasalle and Oglesby, showing a total thickness of 2<> t 
25 feet of limestone. 
The following geologic section at Lasalle, Lasalle County, will serv 
to indicate the position of one of the principal beds of Coal Measur 
limestone. The beds are given in descending order, and bed No. 
is the limestone used by the three Portland-cement plants located 8; 
and near Lasalle. 
Section at Lasalle, 111. h 
i. 
(1) Shales 
(2) Blue limestone 
(3) Bituminous shale and coal . . . 
(4) Shales 
(5) Limestone 
(6) Bituminous shale and coal . . . 
(7) Fire clay (sometimes absent). 
(8) Shale 
(9 ) Limestone 
(10) Shale. 
Feet, 
37 
1 
2 
32 
20 
36 
17 
2 
a The fourth plant uses slag. 
b Report Illinois Board World's Tair Commissioners, 1893, p. 129. 
I'i 
