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 bods 

 //. Sbalo bc;d.>. 



The dip of these beds is to the southeast. 



11. Manidowwh River. — At the mouth of this river, a hard, compact amygdaloid, 

 containing small, siliceous nodules, and veins of laumonite and calcareous spar, forms 



4^ 



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 



