CLARKE.] 
IGNEOUS AND CRYSTALLINE ROCKS. 
6. MESABI DISTRICT, MINNESOTA. 
93 
The following rocks, described by Leith in Mon. XLIII, do not fall 
legitimately within this section of the present bulletin. There seems. 
however, to be no other convenient place for them, and so the niceties 
of classification have been ignored for reasons of expediency. 
A. Greenalite rock, test pit, Cincinnati mine. Contains green and 
brown transparent granules, with opaque brown to black ones, in a 
matrix of chert. 
B. Greenalite rock, same locality as A. Contains greenish yellow 
granules, slightly altered to amphibole in a matrix of amphibole with 
subordinate chert. 
C. Greenalite rock, near W. quarter post, sec. 35, T. 59 N., R. 15 
W. Resembles A. 
D. Greenalite rock, near SE. corner of sec. 22, T. 59 N., R. 15 W. 
Contains yellowish-brown, transparent, and dark-brown to black and 
opaque granules in a matrix which is mainly amphibole, possibly 
actinolite. All four rocks contain oxides of iron, either limonite or 
magnetite. 
Analyses by George Steiger, record Nos. 1931 and 1992. In three 
of the rocks the portions soluble and insoluble in hydrochloric acid 
were analyzed separately. 
A. 
B. 
c. 
Insoluble. 
Soluble. 
Insoluble. 
Soluble. 
Insoluble. 
Soluble. 
Si0 2 
36. 50 
.76 
19.30 
.61 
13. 83 
17. 57 
3.22 
none 
none 
2.38 
5.74 
none 
none 
none 
13. 01 
2.60 


33.11 
.56 
6.44 
30. 93 
5. 35 
none 
none 
1.34 
6. L3 
none 
none 
none 
48. 45 
| .64 
:::::::: 
13. 45 
.37 
15.00 
10.28 
2. 33 
.28 
none 
2.50 
4.17 
none 
2.04 
none 
50 ( i<; 
A1 2 0, 
1 09 
FeA 
FeO 
5.01 
30. 37 
MgO 
5.26 
CaO 
.04 
Alkalies 
none 
H 2 0at 105° 
.75 
H 2 above 105° 
6.41 
TiO, 
none 
C0 2 
none 
P 2 5 
none 
C (organic) 
.21 
Insoluble 
37.26 
62.65 
37.26 
15. 61 
83. 86 
15. 61 
49.09 
50.42 
49.09 
LOO. 10 

99.91 
99.47 
99. 51 1 
