ECKEL.] 
MICHIGAN". 
203 
f 1 the surface clays and frequently form the hills and upland. In numerous instances 
they are used in the manufacture of bricks, titles, etc., although in general not well 
adapted for this purpose. On account of their usual sandy and stony character and 
irregularities in composition, they are seldom worth investigating in reference to the 
making of Portland cement. In some exceptional instances, however, the glacial 
clays are essentially free from gravel and sand, but contain at intervals irregular 
nodules of calcium carbonate, which, if the material were used in making cement, 
would necessitate great care in mixing and grinding to form a slurry. 
The chemical composition of typical examples of drift clay, when free from gravel 
and sand, is here presented: 
Analyses of drift days. 
Constituent. 
l 
2 
3 
4 
5 

Silica (SiOj) 
Alumina ( A1 2 3 ) 
54. 94 
12.14 
4.88 
9.13 
45. 27 
15. 33 
6.65 
11. 32 
46.22 
15. 02 
5.49 
10. 85 
40.15 
11.25 
4.88 
• 21. 43 
8.93 
41.86 
10. 70 
5.02 
14. 33 
52.26 
22. 95 
Ferric oxide ( Fe 2 3 ) 
Lime (CaO) 
8.15 
4.48 
Calcium carbonate ( CaCO 5 ) . . 
Magnesia (MgO) 
3.65 
4. OS 
4.52 
2.81 
1.32 
Magnesium carbonate (MgC0 3 ) 
Sulphuric anhydride (S0 3 ) ... 
Carbon dioxide ( C0 2 ) 
None. 
Trace. 
Trace. 
14.56 
2.80J 
8.00 
Sodium oxide ( Na 2 ) 
(?) 
(?) 
12.44 
| 2.06 
11.30 
Potassium oxide (K 2 0) 
Water and organic matter a 
Sand 
13. 75 
3.44 
15.31 
1.20 
10. 56 
Total 
97.16 
98.84 
98.61 
100. 08 
99.72 
« Loss on ignition. 
1. Brickyard near Pinckney, Livingston County. Furnished by Standard Portland Cement Com- 
pany. Analysis by E. D. Campbell. 
2. From 3 miles north of Jackson. Furnished by Standard Portland Cement Company. Analysis 
byE. D. Campbell. 
3. From near Stockbridge, Ingham County. Analysis by E. D. Campbell. 
4. From Ionia, Ionia County. Analysis by A. N. Clark. Geol. Survey Michigan, vol. 8, pt. 1, 1900, 
pp. 51-53. 
5. From near Jackson, Jackson Countv. Analysis by H. Ries. Geol. Survey Michigan, vol. 8, pt. 1, 
1900, pp. 56-59. 
6. From Springport Township, Jackson County. Analysis by Mariner and Hoskins. Geol. Survey 
Michigan, vol. 8, pt. 1, 1900, p. 60. 
The lake clays are well represented, especially about the border of the southern 
peninsula, as between Detroit and Ypsilanti, about Port Huron, South Haven, 
widely over the Saginaw Valley, and in numerous local basins throughout the State. 
In the Upper Pensinsula extensive deposits of exceedingly fine-grained, laminated 
pinkish clay, deposited from the water of Lake Superior when more widely expanded 
than now, occur in abundance at Sault Ste. Marie, and have a wide distribution west- 
ward, as at Marquette, Escanaba, etc. The chemical composition of this extensive 
deposit is indicated by analysis 6 in the following table, which shows that it is suit- 
able for cement making. 
The lake clays here referred to are characteristically fine grained, many times 
almost entirely free from grit, highly plastic, and uniform in com position. As shown 
by numerous chemical analyses, however, they are what are termed "lean clays;" 
