178 COPPER-BEARING ROCKS OF LAKE SUPERIOR. 
Thickness in feet. 
Marvine’s Group “‘b,” or the Ashbed Group ......--..----------------.---- 618 
Mamuine s\ G noun 07) seers see eee) eee ee ee eae 925 
TENG reenstone GV OUP Vale cles totaal te a= teeter eee 1, 200 
The Pheniz Mine, or Subgreenstone Group << amo. mw lee eel) 685 
From the base of the Phoenix Mine Group, to and including the Kingston 
@ome Lom erste ea ey rans weedeat aoe ae aa oa ae 2, 325 
From the Kingston Conglomerate to the Eastern Sandstone (estimated). . 8, 000 
17, 390 
or, say, between 17,000 and 17,500 feet. 
Eastward from Eagle River the several subdivisions of the section thus 
described continue well marked. In this direction the trend of the strata 
changes a degree or two in the mile, curving around more and more to the 
eastward, until, between Agate and Copper Harbors, the N. 62° E. trend of 
Eagle River has become east and west. Still further east, this curving con- 
tinues, until at the end of the point it has become some degrees south of east. 
The dip, too, in the more northerly ranges flattens towards the eastward, 
becoming in the vicinity of the Delaware mine as low as 24°. A still further 
flattening is reported towards Copper Harbor, and then between that and 
the end of the point another increase in the dip angle. 
At Sand Point and thence eastward the Great Conglomerate of the Eagle 
River section is visibly overlaid by an upper series of diabases with strongly 
marked amygdaloids. These beds are well exposed at Hagle Harbor and at 
the several similar peculiarly formed harbors further east, all of which are 
worn in the softer amygdaloids, or in the underlying sandstone, the more 
compact beds forming the long seawalls of the harbors. This peculiar ero- 
sion may be often seen repeated on a smaller scale, as at Eagle Harbor, where 
each thin amygdaloid is worn back into a long narrow gorge, the harder rock 
on the south sloping away at the dip angle, that on the north rising precip- 
itously. 
Fig. 2.—Surface contour and arrangement of beds at Eagle Harbor. Represents a distance of 
about 200 feet. Scale natural. 
The beds seen at Eagle Harbor and thence eastward are clearly likemany 
of those already described as occurring below the Great Conglomerate in the 
