248 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
prehnite. About an eighth of a mile above this, and only a short distance below the 
town line, the west bank of Moose creek exposes the typical melaphyr previously men- 
tioned, characterized by a dark-green color, fine-grain, peculiar irregular fracture and 
large reflecting surfaces of satin-like luster. 
Passing due southwestward about seven miles into the S. W. 4 of Sec. 6 we en- 
counter a dark, fine-grained diabase, occasionally amygdaloidal, with calcite. A vein 
about two inches wide was observed, which carried considerable native copper in films 
and small particles, associated with calcite and epidote. In the rock there are also parti- 
cles of epidote carrying copper. These are in the bed of the brook, and overflowed in 
high water. A short distance above, the rock becomes softer and contains large amyg- 
dules of chlorite with frequently a core of calcite. These ledges extend along the 
stream for about half a mile. At the dam, near the town line, there is a ledge of highly- 
altered diabase-amygdaloid containing calcite, chlorite and epidote. 
* * * * * * * * * 
To the west of the center of Sec. 8, T. 43, R. 13 W., there is a fine exposure of 
conglomerate, having a dip of about 14° in a direction 8. 50° E. It is traversed by 
two regular systems of joints on courses N. 34° HK. and N. 56° W., by reason of which 
it is eut into regular cubical blocks. Judging from the drift, the western portion of 
the S. E. 4 of the adjoining See. 5 is underlaid by conglomerate. 
Passing over an interval of about five miles, in which no outcrops are known to 
exist, we find in the S. E. 4 of Sec. 6, T. 43, R. 14 W. a wide, low, northeasterly- 
trending ridge, presenting bared rock at one point, which appears to be a diabase 
of very fine, close grain, and dark color, coated with a thin, light-colored crust due 
to weathering. In the N. E. 4 of See. 9 of this township there is a ridge composed 
of rather soft, fine-grained, dark, reddish-brown diabase amygdaloid (specimen 425), 
weathering to a dirty lilac hue. It appears to be much altered. This ridge, in common 
with those of the vicinity, presents an abrupt declivity on the northwest and a gentle 
slope in the opposite direction, the same phenomenon observed so frequently on the 
opposite side of the Saint Croix Valley, but reversed in direction. It is scarcely nec- 
essary to repeat that it is due to the inclination of the strata whose projecting edges 
form the ridges. 
In the S. W. 4 of Sec. 10 (T. 43, R. 14 W.) there is a similar ridge composed of 
melaphyr, and already referred to. A short distance south of this, in the adjoining sec- 
tion (N. W. 4 of Sec. 15), there is a similar ridge, but of diabase, beyond which is still 
another, the rock of which is a dark brown and black, hard, fine-grained crystalline 
diabase, containing occasional amygdules of chlorite. It resists weathering well, and 
only shows a thin, light, dirty grayish coating of weathered substance. The trend of 
these ridges is northeasterly with the strike of the strata. 
In the 8S. W. 4 of See. 15 (T. 43, R. 14 W.), in a large hill, there is a small denuded 
area of rock, of hard, close, minutely crystalline texture, reddish-brown coler, and 
rough, uneven fracture. It contains scattered aggregations of chlorite. It appears 
to be an altered melaphyr. 
In the 8. EB. 4 of Sec. 17 (L. 43, R. 14 W.) there is a long ridge of melaphyr that 
appears to be a continuation of that above noted in Sec. 10, and is probably to be 
correlated with that in Sec. 2, T. 44, R. 13 W., and that at the falls on Chase’s brook, 
Sec. 16 (T. 42, R. 15 W.). There is a like rock found near the center of the west line of 
the N. W. 4 of Sec. 21. 
