328 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
mottled olivine-diabase or melaphyr, the olivine in which is wholly altered 
to a reddish and greenish material. This rock is alluded to further on. 
Just above Manitou River, Sec. 10, T. 57, R. 6 W., 15 to 20 feet of red 
shaly sandstone may be seen overlain by an amygdaloid, and this in turn 
by a columnar diabase. Numerous fragments of amygdaloid and decom- 
posed diabase are contained in the sandstone. The fragments are all angu- 
lar and under an inch in diameter. The occurrence of seams of red shale 
at the mouth of Temperance River has already been mentioned, and the 
peculiar irregularities to which these seams are subject shown in Fig. 27. 
A mile and a half below the mouth of Poplar River, in the northwest corner 
of Sec. 35, T. 60, R. 3 W., six feet of a conglomerate are seen overlain by 
black melaphyr or fine-grained olivine diabase. The pebbles are larger 
below, reaching four inches in diameter, and are principally of red felsite. 
Many are, however, of various types of amygdaloid and diabase-porphyrite. 
Several thin sections were made of these pebbles, and in all the amount of 
non-polarizing unindividualized matrix seemed unusually large, suggesting 
the possible origin of these balls as volcanic scoriz. 
At the mouth of the creek in the 8S. W. 4, Sec. 19; T. 60, R. 2 W., the 
following section was noticed; the order is an ascending one: 
1. Highly vesicular amygdaloid -----..- 2... on oe eee ne mae ee 2 feet. 
2. Fine-grained diabase, including (a) basal amygdaloid, 1 foot; (b) less 
amygdaloidal, 1 foot; (¢) massive portion, 8-12 feet; (d) very irregu- 
lar summit amygdaloid, 6 inches to 2 feet; in all about............. 15 feet. 
3. Red shaly sandstone, bunchy, irregular, mingled with the amygdaloid, 
IHNEN WG aeaccaac w rd) Sw Sis ca evap ain font aration Oe Sra OPE IOUS < CRIM rea 2 feet. 
4, “Amygdaloidl) cinerea sectors eco oe ice rer erstennie or oe ee ae einen eeterereas 4 inches. 
5. Sandstone: os 225 <2 heehee oe kc were co syareeree aerate eiaeis eval Ses eee errr 6 inches. 
G:, Amy daloid ia: feecertesrercriee elas epee eae eee eae Foasnaes soso Sbs6 2 feet. 
Te, SANASbONGE sero <a) see wets Saseeeieeellcte ee eee AEC mn ena dos 3 inches. 
8: Massive melaphiyi.ca.-temiecereriecioe - eles eee eee SOLS Rat lageieepessre eerste .. LO feet. 
The seams 3 to 7, inclusive, are very irregular, and in all the sand- 
stone probably belongs to one horizon. 
In the bay immediately behind Caribou Point, 8. W. 4, Sec. 11, T. 60, 
R. 2 W., red shaly sandstone underlies an excessively fine-grained but 
wholly typical melaphyr or olivine-diabase. Some twelve feet of the mela- 
phyr and twenty of the sandstone are in sight. The large bay here is 
