IGNEOUS AND CRYSTALLINE ROCKS. 55 
H. Amphibolitic chert, one-half mile southwest of Virginia. P. R. C. 1675. 
I. Amphibolitic chert, Donora mine. P. R. C. 1676. 
G, H, and I are largely amphibole in a matrix of chert. Analyses by George Steiger, 
record Nos. 1931, 1948. 
8 MISCELLANEOUS ROCKS FROM MINNESOTA. 
A. Granulitic hypersthene gabbro, from SE. } sec. 20, T. 65 N., R.4 W. Cookose. 
Described by Bayley, Jour. Geology, vol. 3, p. 1. Contains hypersthene, biotite, 
diallage, magnetite, and plagioclase. Analysis by H. N. Stokes, record No. 1267. 
B. Hypersthene from A. Analysis by E. A. Schneider, record No. 1358. 
C. Granulitic diallage gabbro, SE. } NW. } sec. 26, T. 64N., R.8 W Auvergnose. 
Described by Bayley, Jour. Geology, vol. 3, p. 1. Contains diallage, hypersthene, 
_ magnetite, and plagioclase. Analysis by W. H. Melville, record No. 1403. 
D. Olivine gabbro, west side of Birch Lake, SE. }sec.19, T.63N.,R.4W. Auverg- 
nose. Described by Bailey, Jour. Geology, vol. 1, p. 688. Contains a large proportion 
of diallage and olivine. Analysis by Stokes, No. 1267. 
E. Olivine from D. Analysis by W. F. Hillebrand, record No. 1308. 
A B Cc. D E 
SiO. asiccis za Wisinee nee eee rere eoreeineer ene reveetaens 46.96 | 48.44] 49.56 | 45.66 35. 58 
BRISO9) ocrorie eninge e2uinbancemas po eeceeeetes Been ese 14.13 7.91 | 17.81] 16.44 92 
FegQ3.....---- -76 +33 2.76 66 33.91 
FeO. 14.95 | 20.88 9.48 | 18.90 |f....-.- 
MgO 15.97 | 19.35 5.93 | 11.57 26. 86 
CaO. 2. 32 1.44 9.70 7.23 90 
Na,O HOD: |howseee: 2.87 DAS: lates ate 
KoQheteeccvwevbam ne cw onus sametcuiidaes raeeetecines = ae sae VB locas crac |eieccemacacs oA No reicsaracsts 
HoO! at) 105 0 a-< sseees cedtopeme.s tose stems apse tesreee gata rai -07 - 08 ti 50 07 11 
H20 above 105°... -| 1.26] none e - 83 20 
TiOg.....- 62 | undet. -48 -92 1.22 
P.O; - 03 farses -67 205 Joeman 
CraQOz. trace: |eccicesce Hectseee: trace trace 
MnO. 93 92 06 | trace 35 
COO aes sedis ciacccarsearemdesie aot pee Sen mares vera iar ler ee tines ieds Meeeereleicueinss anes mae | eee siete blesses od [eset 
INTO fectcecbectstce tes ceectcstecere ay ee cae arrange id beaceeeel Iercase 16 \ 20 
CO tie xcsewaeeedenas to ceciesenuanxsmtemeniee sae de temas siaieecer|seesades |atecedae GRACE” ob ccece cell pienszee® 
100.09 | 99.35 | 99.82 | 100.03 | 100.25 
F. Average gabbro, south quarter post, sec. 35, T. 61 N., R. 12 W. Hessose. De- 
scribed by Bayley'in Jour. Geology, vol. 1, p. 688. Contains plagioclase, olivine, 
pyroxene, and magnetite. Analysis by H. N. Stokes, record No. 1267. 
G. Feldspar, from preceding gabbro. Analysis by W. F. Hillebrand, record 
No. 1308. 
H. Feldspar, from gabbro east side of North Fowl Lake. Analysis by Hillebrand, 
No. 1308. 
