OLIVINITIC DIABASE—MELAPHYR. 
cluding melaphyrs)—Continued. 
75 
Tabulation of the results of a microscopic study of fine-grained olivinitic diabases (in- 
Angle between 
maximum ex- 
tinctions of 
adjacent hemi- 
tropic bands of 
§ i : ; y the plagioclase 
Plages 8 Macroscopic char- Constituents as determined by in sections cut 
g Be} acters. microscope, in order of age. at random in 
a 3 » the zone O: 73. 
§ 3 ; = 3 Angles on| 2 . 
a s 3 é & opposite so 
2 ref (OP fel le sides of E 3 
a) SPlalal & cross-hair. 
° ° ° 
365 S...| Totogatig district, 12 | 44 |9W. | Fine-grained, | Olivine, wholly altered to red | 31 36 67 
Douglas County, compact, red- product; labradorite or an-| 35 31 66 
Wisconsin. dish-brown, orthite ; very little magnetite ; 
small and in- Qugite, in large individuals 
conspicuous enveloping the feldspar crys- 
“luster-mot- tals, 
tlings.” 
400 S...| Moose Creek, |NW.| 2 | 44 |13W.|...........-..-..... Olivine, abundant, altered | 37 37 74 
Douglas County, wholly to a soft green sub-| 22 23 45 
Wisconsin. stance, crowded as usual into 
the interspaces of the angites; 
labradorite or anorthite ; mag- 
netite, chiefly in the augite in- 
terspaces ; augite, in large in- 
dividuals, including countless 
small crystals of feldspar; 
pseud-amygdules of chloritic 
substance. Resembles ex- 
actly the rock of ‘The Green- 
stone " of Keweenaw Point. 
rC Beoes Near the upper | SW.| 15 | 43 |14W.| Fine-grained, Olivine, altered to a greenand | 30 | 37 | 67 
Saint Croix bright red, al- red product; plagioclase, | 34 | 32 | 66 
River, Douglas tered. Sp. gr., fresh; augite, fresh; chlorite | 35 39 74 
County, Wis- 2.90. pseud-amygdules. 
consin. 
(3 Paar Bed of Lester|NW.| 4! 50/13. Medium - grained, | Olivine, abundant, wholly al- 
River, Minne- | cor. erystalline, tered to dark green substance, 
sota, north bright red, mot- crossed by deep brown and 
shore Lake Su- tled with green red, to which alteration the 
perior. and black, color of the rock is due; 
plagioclase partly fresh, part- 
ly clouded; augite, fresh, in 
large areas including many 
feldspars; pseud-amygdules 
of chlorite. 
568... .. North shore Lake | NW.| 17 | 51 | 12 W.| Fine- grained, | Olivine, altered to green sub- | 25 25 50 
Superior, falls rough fracture, stance, and crowded into the | 29 32 61 
of French River, dark purplish- augite interspaces with the| 28 28 56 
Minnesota. brown, ‘‘luster- magnetite; labradorite ; mag- 
mottlings” not 
netite; augite, in the usual 
pronounced. large areas. 
TI ee | 
