46 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
Fabulation of observations on coarse orthoclase-free gabbro-and diabase—Continued. 
Angle between 
maximum ex- 
tinctions of 
adjacent hemi- 
Z tropic bands of 
s ; : the plagioclase 
F| Place. & Mecrenang chor- Constituents as determined by | {i sections: ous 
z 5 F microscope, in order of age. tiewone Ose 
g Seal rere 
E z < é Sp opposite og 
2 = $| 6 sides of | 4g 
n OC ln/aA es cross-hair.| & © 
° ° ° 
84S...| Brunschweiler’s |NW.| 11 | 44 | 4 W.| Coarse-grained; | Olivine, partly altered; labra-| 22 25 47 
River, Ashland dark-gray, mot- dorite ; titaniferous magnetite; | 28 29 57 
County, Wis- tled with white. diallagic augite; secondary | 18 18 36 
consin. Sp. gr., 2.92. biotite, viridite, ochre. 
158 W.| Ashland County, | NE. | 15 | 45 | 4 W.| Coarse-grained; | Labradorite ; titaniferous mag- 
Wisconsin. light-gray. Sp. netite; diallage sparse, partly 
gr., 2.81. changed to wralite. 
164W!, Brunschweiler’s 22 | 45 | 4 W.| Fine-grained; | Anorthite; magnetite; diallage; | 30 37 67 
River, Ashland dark-gray; lus-| a little biotite. 33 | 36 | 69 
County, Wis- trous. 36 32 68 
consin. 
861?...| Ashland County, | SE. | 14 | 44 | 5 W.| Very coarse-grain- | Labradorite; titanifcrous mag- 
Wisconsin. ed; light-gray. netite: diallagic augite, uralite. 
1132...| King’s Creek, near} NE. | 12 | 49 |15 W.|.....-..-..-.-.---.- Apatite; olivine more altered | 32 27 59 
Duluth, Minn. than in the last section; | 34 38 72 
anorthite; titaniferous mag-| 29 35 64 
netite; diallage; biotiteina| 31 33 64 
few flakes; ferrite. 
Tbe Brewery Creek, | SE, | 22 | 50 |14 W.) Medium-grained; | Olivine, highly altered; anorth- | 29 32 61 
near Duluth, dark-gray to ite; titaniferous magnetite; | 30 37 67 
Minn. nearly black; augite in part diallagic; altera-| 18 27 | 45 
rough-textured. tion-product of augite. 33 37 70 
Sp. gr., 2.91. BW || Pre || ex 
23 21 44 
1103...| Falls of Cloquet | SE. | 34 | 53 |14 W.| Coarse-grained; | Apatite; olivine, mostly fresh, | 26 | 25 | 49 
River, Minne- very light-gray. partly altered to green sub-| 35 33 68 
sota. 400N.,200 stances, and red and brown | 24 26 50 
W.3 iron oxides; anorthite; titan- | 33 34 67 
iferous magnetite; diallage ; 
biotite in a few small flakes; 
JSerrite. 
621....| Duluth, Minn., 27 | 50 |14W.| Medium-grained; | Anorthite; titaniferous magne- | 34 38 72 
near center of nearly black; tite, in elongated parallelrods; | 33 31 64 
rough-textured. augite, in part diallagic ; light | 38 40 78 
green alteration-product of 
augite. 
§28....| North shore Lake | NW.| 24 | 50 |14 W.| Medium-grained ..| Olivine; anorthite ; titaniferous | 23 24 | 47 
Superior. magnetite ; augite,inpartdial- | 21 19 40 
lagic, in large crystals, en- | 20 21 41 
closing many feldspars. 39 32 71 
17 16 33 
28 25 53 
1 Vol III, Geology of Wisconsin, p. 39. 
2 Vol. III, Geology of Wisconsin, p. 40. 
$400 paces north and 200 paces west of the southeast corner of the section; 2,000 paces to the mile. 
