204 
CEMENT MATERIALS AND INDUSTRY. 
[BULL. 24c 
that is, not high in alumina and ferric oxide in proportion to the silica present, an< 
not, as a rule, considered favorable for cement making. These properties and th 
usual presence of lime, together with the frequent occurrence of sulphuric anhydride 
are shown by the following analyses: 
Analyses of lacustral clays. 
( 'onstituent. 
Sand 
Silica (Si0 2 ) 
Alumina ( A1 2 3 ) 
Ferric oxide ( Fe 2 3 ) 
Lime (CaO) 
Calcium carbonate (CaC0 3 )... 
Magnesia (MgO) 
Magnesium carbonate ( MgC0 3 ) 
Sulphuric anhydride (S0 3 ) 
Sodium oxide (Na 2 0) 
Potassium oxide (K 2 0) 
Water (H,0) 
49. 75 
13.06 
5.31 
10.86 
49.34 
14.50 
5.37 
9.75 
1.51 
66.49 
9.87 
4.87 
4.72 
47.75 
17. 60 
9.13 
(?) 
46.40 
}16.4{ 
2.60 
4.28 
4.77 
1.22 
.70 
25.36 
4.30 
(?) 
(?) 
"15.07 
.13 
(?) 
(?) 
« 15. 55 
.62 
(?) 
(?) 
« 9. 36 
} 2 - 21 { 
22.01 
.00 
Total 
99.13 
99. 25 
98.66 
100.00 
99.46 
61.65 
17. 2( 
5. J 
5.65 
: 
2.85 
It 
«5.34i 
99. 0C 
a Loss on ignition. 
1. From near Chelsea, Washtenaw County. Analysis by E. D. Campbell. 
2. From near Fenton, Genesee County. Analysis by E. D. Campbell. 
3. From near Farmington, Oakland County. Analysis by E. D. Campbell. 
4. From near Saginaw. Analysis by H. Reis. Geol. Survey Michigan, vol. 8, pt. 1, 
5. From Wyandotte; used in cement making by the Michigan Alkali Company. 
Button. 
6. Sault Ste. Marie. Analysis by E. D. Campbell. 
1900, p. 55. 
Analysis by 0.» 
The river silts occur on the border of many streams, sometimes in terraces a few 
feet above their surfaces. Although in many instances available for brick and tile 
making, they are usually too sandy to be employed in manufacturing Portland 
cement without being ground, so as to have the requisite degree of fineness — that is, 
so as to pass through a sieve with 150 to 200 meshes to the linear inch. No analyses 
of typical examples of the river silts are available, but as the deposits are derived I 
mainly from the drift clays, they no doubt have the same composition, lacking, 
perhaps, some of the calcium carbonate and alkaline salts. 
In general it may be said that the surface clays of the Southern Peninsula are not 
favorable for use in making Portland cement, although some of the stony clays, if 
crushed sufficiently fine, may be employed for that purpose. Reference is not here 
made to the decomposed outcrop of the shales described in the preceding section, 
which might perhaps be taken for surface clays, some of which have been used with 
favorable results. In reference to the surface clays of the Northern Peninsula little 
accurate information is available, excepting the analysis of a representative sample of 
the extensive deposit of pink clay near Sault Ste. Marie, given above. 
In a summary of the results of Pdes's investigations of the shales and clays of 
Michigan, already referred to several times, A. N. Clark remarks as follows: « 
" For use in the manufacture of Portland cement the shales of the Cold water series 
are best adapted. The shales of the Michigan series are also good if not too high in 
a Geol. Survey Michigan, vol. 8, pt. 1, 1904, p. 64. 
