414 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
line of the Point and the course of the constituent rock belts swing around 
to the southwest. Correspondingly, we find, on the North Shore, a southwest 
trend (participated in by rock belts, coast lines, and lines of islands), begin- 
ning in the western part of Isle Saint Ignace, and continuing through the 
peninsula which forms the south side of Black Bay, through the adjoining 
islands, and through Isle Royale. 
Isle Royale does not lie on a straight course, but on a curving one, 
its outlines, projecting points, ridges and rock belts at the western extremity 
trending 10° to 12° more to the south than at the eastern extremity. This 
curvature to the westward is continued to a nearly due westerly direction 
in the rock belts, projecting points and other topographical features of the 
Minnesota coast between Pigeon River and Grand Marais, although the 
coast line in this distance trends as a whole some 20° south of west. The 
counterpart of this swing to the west is found on the south shore of Lake 
Superior in the course of the Main Trap Range and its constituent rock 
belts, and of the coast line between Fourteen-mile Point and Black River. 
West of Black River, the Main Trap Range of the South Shore and its 
rock beds curve again to the south of west, and as Bad River is neared the 
direction is only some 30° west of south. The corresponding curvature on 
the North Shore is to be found in the distance between Grand Marais and 
Split Rock River. For much of this distance the coast line follows the 
trend of the strata, until the latter comes around to only a few degrees 
west of south, when the rock belts depart from the coast, and run with a 
eastward curvature over to the South Shore. Still further west, both sides 
of the synclinal are on the South Shore, the strata, and with them many 
topographical features, on both sides, trending at first well around to the 
west, and then more and more towards the south, until the termination is 
reached in the Saint Croix Valley. 
Beyond Copper Harbor to the eastward, on Keweenaw Point, the point 
and its strata begin to swing around to the south of east, and this direction 
is continued on Manitou Island, and in Stannard’s Rock, which is, as pre- 
viously shown, a mass of quartzless porphyry. Parallel to this curving 
course is the coast line of the lake between Huron Bay and Marquette. 
Now on the North Shore, in the line of islands lying south of Nipigon 
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