200 
CEMENT MATERIALS AND INDUSTRY. 
[BULL. 243. 
Other analyses of the shales of this formation occurring near Bronson, Cold water, 
and at White Rock, compiled from Ries's report, are as follows: 
Analyses of Coldwater shale. 
[Analyst, H. Ries.] 
Constituent, 
Silica (Si0 2 ) 
Alumina ( A1 2 3 ) 
Ferric oxide ( Fe 2 3 ) 
Calcium (CaO) 
Calcium carbonate (CaC0 3 ) 
Magnesium (MgO) 
Magnesium carbonate (MgC0 3 ) 
Sulphuric anhydride (S0 3 ) 
Alkalies (Na 2 and K 2 0) 
Water and organic matter 
Total 
Bronson. 
62.10 
20.09 
7.81 
.65 
.96 
.49 
7.90 
100. 00 
Coldwater. 
53. 44 
24.80 
25 
20.75 
100. 00 
White Rock. 
58. 70 
18.31 
1.8Q 
.98 
3. 67 ; 
9.35J 
100.00 
The Coldwater shales occur beneath the surficial deposits throughout an extensive- 
area in the southern peninsula, * * * but are seldom well exposed at the surface. 
As noted by Ries,« however, extensive outcrops occur along the shore of Lake Huron . 
between White Rock and Forsyth, and are favorably situated for shipping by water. . 
At many localities where suitable surface clays can not be had in connection withi 
extensive marl deposits it may be found practicable to mine the underlying Coldwater i 
shales, as was formerly done near Bronson, for use in cement making. 
ANTRIM SHALES. 
In addition to the deposits briefly described above, there are two formations in 
the southern peninsula which contain shales that, in certain instances, at least, are* 
worth investigating in connection with the industry here considered. These are the* 
Antrim shales, which occur at the summit of the Devonian system, and the Saginaw 
formation, which forms the upper portion of the Carboniferous system as developed 
in Michigan. 
The Antrim shales usually contain a high percentage of organic matter and yield i 
petroleum, gas, etc., on distillation. No attempts have yet been made to utilize 
them for making cement, although their physical properties (except, perhaps, their' 
toughness, which renders them somewhat difficult to quarry or to reduce to a pow- 
der) and their chemical composition make them worthy of experiment in that con-> 
nection. An analysis of probably un weathered Antrim shale, made for the purpose » 
of testing its fuel value, published by Ries, 6 is as follows: 
Analysis of Antrim shale. 
[Analyst, W. H. Johnson.]* 
Volatile matter 17. 96 
Fixed carbon 6. 49 
Ash , 75. 55 
Total 100. 0C 
aGeol. Survey Michigan, vol. 8, Pt. I, 1900, p. 44. 
b Ibid p. 47. 
