222 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
in the interstices of the grains, and in some sections is the only indurating 
material. 
From the Nonesuch mine eastward the shale belt runs through the 
southern parts of sections 6 and 5 of T.50, R. 42 W. In the latter section 
the lower layers, including the Nonesuch bed, which is here also well 
charged with copper, are exposed on Mineral River at 250 paces north 
and 450 west of the southeast corner, with a southerly dip of 40°. From 
here the course of the belt makes a wide bow through sections 4 and 3, T. 
50, R. 42 W., and sections 31 and 30 of T. 50, R. 41 W., to Mineral River, in 
Sec. 25, T. 51, R. 42 W., where itis seen exposed (1,200 N., 200 W.), with 
a northeasterly dip. In the same section, on Iron River (1,750 N.,800 We), 
the junction with the underlying sandstone is again seen, and both rocks 
make here a sharp turn from a northwesterly to a northeasterly course, the 
dip at the same time being changed from a northeasterly direction to a 
southeasterly one. 
The course of the belt is next on a bow to the eastward through Sec. 
19, T. 51, R. 41 W., returning to Iron River in the 8. E. 4, Sec. 13, T. 51, R. 
42 W. Here Iron River crosses the whole width of the belt, exposing both 
the underlying and overlying sandstones. The dip here is 35° east of north, 
and the thickness of the belt 600 feet. From here the course is westward 
to Little Iron River, in the 8. W. 4, Sec. 13. At this place there is a sharp 
synclinal, the belt turning abruptly and showing southerly dips. Return- 
ing now eastward to Iron River, the junction with the overlying sandstone 
is found in the northeast quarter of the same section (1,150 N., 250 W.), 
Thence to its mouth, Iron River is constantly on the layers of this belt, an 
anticlinal occurring near the N. E. 4 of Sec. 13. The turns of the shale and 
of its overlying and underlying sandstones will be best understood by an 
inspection of the sections of Plates XX and XXI, and of the strike and dip 
notes of Plate XIX. At the mouth of Iron River the shale belt passes into 
the lake with a northwesterly trend, the junction with the overlying sand- 
stone appearing just at the mouth of Iron River, and with the underlying 
on the lake shore on the west side of the N. E. 4 of the N. W.4, Sec. 12, T. 
51, R.42 W. In all of these exposures between the Nonesuch mine and the 
mouth of Iron River the subordinate bedding of the shale stratum remains 
