ORTHOCLASE-FREE GABBRO. 
49 
Tabulation of observations on coarse orthoclase-free gabbro and diabase—Continued. 
Specimen number. 
1007... 
1515... 
1528... 
Beaver River, 
Minnesota, 875 
N., 1,600 W. 
Four miles north 
of Beaver Bay, 
Minnesota. 
Six miles north 
of Beaver Bay, 
Minnesota. 
Eight miles north 
of north line of 
Beaver Bay, 
Minnesota. 
North shore Lake 
Superior; north 
point of Beaver 
Bay, Minnesota. 
Island northeast 
of Beaver Bay, 
Minnesota. 
North shore Lake 
Superior; near 
mouth of Brulé 
River, 
sota, 
Minne- 
North shore Lake 
Superior; about 
13 miles east of 
Mawskequaw- 
camaw River, 
Minnesota, 
1012... 
1021... 
819... 
pales 
| 
Angle between 
maximum ex- 
tinctions of 
adjacent hemi- 
tropic bands of 
the plagioclase 
a Macroscopic char- | Constituents as determined by in sections cut 
& acters. microscope, in order of age. at random in 
) ‘ the zone O: it 
a | | & 7 
£/8{3| ¢ Angee et a 
a ||| 4 COLO SE 
Se [ie EV | cross-hair.| a 
° ° ° 
SW. | 12 | 55 |8W.| Medium-grained; | Anorthite, greatly predeminat- | 28 27 55 
red-and-black- ing; titaniferous magnetite; | 29 25 54 
mottled; very diallage. 30 30 60 
large diallage 23 24 52 
luster-mottlings. 33 35 «68 
NW. ! 25 | 56 | 8 W. | Medium-grainedto! Olivine, large, abundant and! 30 27 57 
coarse- grained ; very fresh; anorthite ; titanif- | 23 25 48 
gray; rough- erousmagnetite ; augiteinpart | 35 39 7 
textured. diallagic. 37 37 74 
NE. | 13 | 56 | 8W. | Medium-grainedto| Anorthite; titaniferous magnet- | 32 38 70 
coarse- grained; ite; augite, very muchaltered; | 31 82 63 
black; rough- diallage; much ochre and fer- | 25 30 55 
textured. rite. 
NE.; 2) 56|8W.| White-and-green- | Labradorite, much clouded; | 24 25 49 
mottled ; rongh- titaniferous magnetic, very 
textured. abundant and coarse ; diallage, 
largely altered to greenish 
5 dichroic uralite.! 
NW.| 7) 55|7W.| Medium-grainedto| Olivine, very abundant and | 24 24 48 
coarse - grained ; large, largely altered to the | 23 30 53 
black; rough- characteristic brown sub-| 31 25 56 
textured. stance; labradorite; titanifer- | 31 29 60 
ous magnetite; non-diallagic 
augite largely altered to green- 
ish material. 
NW.) 5/55 |7W./} Medium-grained; | Anorthite; titaniferous magnet- | 33 35 68 
black; rough- ite; augitein very large areas; | 32 44 76 
textured. diallage ; viriditeasalteration-| 32 37 69 
product of augite. 36 35 71 
INE | 3441} 62'S. | Coarse:e rained 'ss|te- asset snsncn canes ooenwe ne one 20 22 42 
nearly black; 36 31 67 
rough-textured; 38 35 73 
shows brassy 36 33 69 
diallage on 
weathered sur- 
face. 
(abou|t) 5 | 62 | 5 E. | Medium-grainedto| Labradorite; titaniferous mag-| 25 29 54 
(un|suriveyjed). fine-grained; netite; augite, non-diallagic, | 15 14 29 
very dark-gray ; much altered to viridite mate- | 20 18 38 
rough-textured. 
rial. 
1 The green appearance of the rock to the naked eye is evidently connected with this uralitic change. 
5b ins 
Peal 
