eel oF a, 
OLIVINE-FREE DIABASE. 
67 
Tabulation of observations upon fine-grained olivine-free diabases of the “ordinary type”— 
Continued. 
Specimen number. 
1966... 
2526... 
2529... 
22 W. 
26 W 
Place. 
Bed 87, Eagle 
River section, 
Keweenaw 
Point, Michi- 
gan; middle 
zone.! 
Bed 69, Eagle 
River section.? 
Bohemian Range, 
Keweenaw 
Point, Michi- 
gan. 
Union mine, Por- 
cupine Mount- 
ains, Michigan; 
1,950 north, 1,750 
west. 
Rock underlying 
Union mine 
amygdaloid, 
Porcupine 
Mountains, 
Michigan; 200 
north,1,750 west. 
Ashland County, 
Wisconsin. 
Montreal River, 
Wisconsin, at 
the crossing of 
the Flambeau 
trail. 
1R, Pumpelly, ‘‘Metasomatic Development,” p. 284. 
E 
3 
o 
2 
8 | 4 
inte 
ae 
go |n 
NE. | 30 
NE. | 30 
ee 9 
Nw. | 27 
Sw. | 22 
eaters 34 
Poscce| 24! 
a 
ao 
47 
| Township. 
Range. 
Macroscopic char- 
acter. 
Constituents as determined by 
microscope, in order of age. 
31W. 
31 W. 
31W. 
42 W. 
42 W. 
1E. 
Coarser grained 
than lower zone, 
with numerous 
pink feldspars 
and large 
bunches of chlo- 
rite. Sp.gr., 2.73 
to 2.75. 
Fine-grained; 
dirty-green. Sp. 
gr., 2.87 to 2.95. 
Powder yields a 
little magnetite. 
Fine-grained; 
dark brown mot- 
tled with green; 
abundant chlo- 
rite pseud-amyg- 
dules. 
Fine-grained; 
dark purplish- 
brown; abundant 
large calcite 
pseud-amyg- 
dules. 
Fine-grained; 
dark brown mot- 
tled with green- 
ish black; highly 
weathered. Sp. 
gr., 2.85. 
Oligoclase, very much altered; 
augite, wholly changed to 
green pseudomorph with iron- 
stained cracks; large pseud- 
amygdules with dark-green 
chlorite (delessite). 
Plagioclase, largely altered to 
chlorite; magnetite; augite, 
in part fresh, in part changed 
to greenish substance. 
Altered magma;  oligoclase ; 
magnetite ; augite, only rarely 
fresh, mostly altered to green 
substance, with red and black 
chlorite pseud-amygdules. 
Altered magma; labradorite; 
augite wholly altered to green 
and brown pseudomorphs; 
calcite and chlorite pseud- 
amygdules abundant. 
Altered magma; oligoclase; au- 
gite, in part fresh, but mostly 
altered to green substance 
with red bands; abundant 
pseud-amygdaloidal chlorite. 
Oligoclase; magnetite; augite, 
wholly altered; pseud-amyg- 
dules of stellated chlorite and 
calcite; whole rock much 
charged with ferric oxide. 
Anorthite ; augite; chlorite and 
calcite pseud-amygdules. 
2 Tbid., p. 288. 
cross-hair. 
| 
Angle between 
maximum ex- 
tinctions of 
adjacent hemi- 
tropic bands of 
the plagioclase 
in sections cut 
at random in 
the zone O: ii. 
Angles on | 2 
opposite | o 
sidesof| 4g 
ea 
° ° ° 
26 
29 
34 
35 
36 
7 4% 11 
13 | 17 30 
19 | 16 35 
1g | 21 39 
19 | 20 39 
3 8 1 
5 7 12 
