3-i-i APPENDIX. 



4. Iron. 



This mineral is distributed, in several of its forms, throughout 

 the region visited, although but little attention has yet been 

 directed to its exploration. In the basin of Lake Superior it 

 exists, in valuable masses, in the form of a magnetic oxide, on the 

 coasts of the lake between Gitchi Sebing (Great River), called by 

 the French Chocolate River, and Granite Point, Specimens from 

 Dead River (Riviere du Morts) and Carp River, the Namabin of 

 the Indians, in this district, denote the latter to be the chief lo- 

 cality. It is the iron glance, and occurs in mountain masses. 



Sulphuret of Iron. — This variety is found, in limited quantities, 

 in a state of crystallization, in clay beds, on the west shore of 

 Lake Michigan, between Milwankie and Chicago. It is frequently 

 in the form of a cube or an octahedron. Some of the crystals are 

 in lumps of several pounds' weight, with a metallic lustre. Often 

 the masses, on being broken, are found radiated, sometimes cellu- 

 lar, and occasionally irised. 



Iron Sand. — The breaking-up and prostration of the sandstone 

 and other sedimentary formations, along the shores of lakes Michi- 

 gan, Huron, and Superior, liberates this ore in considerable quan- 

 tities. It arranges itself, on the principle of its specific gravities, 

 in separate strata along the sandy shores, where it invariably 

 occupies the lowest position at and below the water's edge. The 

 shores of Fond du Lac, on Lake Superior, may be particularly 

 mentioned as an abundant locality. 



Micaceous Oxide of Iron. — In detached mass, among the debris 

 of the River St. Louis and of Fond du Lac. It exists in veins 

 in the clay slate which characterizes the banks of this river. 



Ochrey Red Oxide of Iron (Red ochre) — Is produced near a spot 

 called the Big Stone, on the head of the River St. Peter's. It is 

 said to occur in a loose form, in a stratum of several inches thick, 

 lying below the soil of a level dry prairie or plain. The Sioux 

 Indians, who employ it as a paint, make this statement. The 

 color of a portion given to me by them is of a bright red; and a 

 considerable proportion of the mass is in a state of minute divi- 

 sion. Particles of quartz are occasionally mixed with it. This 

 ore of iron is also represented to be found in the prairies north of 



