NORTHWEST SHORE OF LAKE SUPERIOR. 367 
escarpment, showing six beds, with thin partings of ferruginous clay and shale 
between them, as represented by the annexed cut. 
a. Trap beds. 
b. Shale beds. 
The dip of these beds is to the southeast. 
11. Manidowish River—At the mouth of this river, a hard, compact amygdaloid, 
containing small, siliceous nodules, and veins of laumonite and calcareous spar, forms 
GORGE, FALL, AND ARCH OF MANIDOWISH RIVER. 
the lower part of the bluff, and is overlaid by conglomerate, which, although brecciated, 
contains many large, rounded pebbles of altered sandstone, amygdaloid, and a coarse 
jaspoid rock. The amygdaloid and conglomerate seem to alternate, as they become 
