320 
ANALYSES OF ROCKS, U. S. GEOLOGICAL SURVEY. [no. 228. 
P. Ferrodolomite, Marquette district, Michigan. Analysis by George 
Steiger, record No. 1473. P. R. C. 994. 
Q. Ferrodolomite, Marquette district, Michigan. 
R. Portion of Q insoluble in hydrochloric acid. 
S. Soluble portion of Q. 
Analysis Q, R, and S by George Steiger, record No. 1442. These 
rocks are not in the monograph cited. 
T. Ferruginous dolomite, Hamburg Hill, Menominee district, 
Michigan. Described by Bayley in Mon. XLYI, p. 480. Analysis 
by George Steiger, record No. 2033. 
r. 
Q. 
R. 
s. 
T. 
Si( )., 
42. 37 
26.97 
1.30 
2.31 
39. 77 
1.94 
.66 
\ . 09 
. 10 
.51 
26. 67 
.12 
.16 
.10 
.30 
1.18 
2.15 
39.77 
1.84 
.66 
\ . 09 
36. 71 
ALA 
5.34 
Fe.,< ), 
1.09 
31.41 
2. 48 
.50 
.35 
FeO 
3.37 
MgO 
10.78 
CaO 
15. 11 
Na.,0 
.12 
K,() 
2.40 
H,0 at 100° 
.55 
H,0 above 100° 
1.61 
Ti0 2 
.27 
C0 2 
21. 80 
26. 20 
.03 
.29 
26. 20 
.03 
.29 
23.22 
P,0- 
05 
MnO 
.23 
99. 65 
100. 1 7 
27. 05 
72. 51 
100. 11 
