20. Schorl. Common. Outlet of Lac du Flambeau. Also, in a detached mass of primitive rock at Green Bay.
21. Feldspar. Porcupine mountains, Lake Superior.
22. Basalt. Amorphous. Granite Point, Lake Superior.
23. Stilbite. Amygdaloid rock, Keweena Point, Lake Superior.
24. Zeolite. Mealy. With the preceding.
25. Zeolite. Radiated. Lake Superior. This mineral consists of fibres, so delicate and firmly united as to appear almost compact, radiating from a centre. Some of the masses produced by this radiation, measure 2.5 inches in diameter. They are of a uniform, pale, yellowish red. This mineral has not been traced in situ, being found in detached masses of rock, and sometimes as water-worn portions of radii. Its true position would seem to be the trap rock.
26. Asbestos. Presque Isle, Lake Superior. In the serpentine formation.
27. Hornblende. Very abundant as a constituent of the primitive rocks on the Upper Mississippi, and in the basin of Lake Superior. Often in distinct crystals.
28. Diallage, green. Lake Superior. In detached masses, connected with primitive boulders. Harder than the species.
29. Serpentine, common. Presque Isle, Lake Superior.