CLARKE.] 
CLAYS AND SOILS. 
359 
ILLINOIS, IOWA, MINNESOTA. 
A, B. Clays from Henry County, Illinois. Analyses by T. M. 
Chatard, record No. 144. 
C. Loess, a stratum overlying residuary clay, 350 feet above the 
Mississippi River, near Galena, Illinois. Described by Chamberlin and 
Salisbury, 6th Ann., p. 282. Analysis by R. B. Riggs, record No. 
293. Dried at 100 \ 
D. Loess, 300 feet above the Mississippi, 3£ miles northwest of 
Dubuque, Iowa. Described by Chamberlin and Salisbury (loc. cit.), 
and analyzed by Riggs, No. 292. Dried at 100°. 
E. Tallow clay, lead mine at Lansing, Iowa. Collected b} r W. P. 
Penney. Analysis by H. N. Stokes, record No. 1337. Dried at 100°. 
Partial analysis. 
F. Greenish-gray clay, New Ulm, Minnesota. Analysis b} r T. M. 
Chatard, record No. 825. 
A. 
B. 
c. 
D. 
E. 
F. 
SiO., 
46.12 
15. 24 
4.41 
42. 58 
12. 16 
3.90 
64.61 
10.64 
2.61 
.51 
3.69 
5. 41 
1. 35 
2.06 
2.05 
.40 
.06 
.05 
72. 68 
12.03 
3.53 
.96 
1.11 
1.59 
1.68 
2.13 
2.50 
.72 
.23 
.06 
52. 08 
23.11 
9.34 
2. 12 
1.04 
undet. 
undet. 
9.80 
trace 
trace 
61. 32 
Al 2 ().. 
12.27 
Fe.,0- 
3 62 
Fe( ) 
4.18 
MgO 
CaO 
3.63 
8.63 
1.54 
3.79 
15. 57 
.79 
.08 
.28 
4.32 
11.33 
1.96 
3.88 
18. 64 
.64 
.10 
.09 
1.76 
.99 
Na,() 
.42 
K 2 
H 2 
3.59 
10.73 
TiO, 
66 
P 2 5 
.27 
MnO 
.27 
ZnO 
PbO 
BaO 
.05 
C0. 2 
6.31 
.13 
.11 
.07 
.39 
. 09 
.51 
.01 
C, organic 
SO, 
19 
CI 
100. 08 
99.60 
100. 06 
100. 22 
97.49 
100. 32 
