1. Calcareous spar. Keweena Point, Lake Superior. Imbedded in small globular masses, in the trap rock; also forming veins in the same formation. Some of the masses break into rhombic forms, and possess a certain but not perfect degree of transparency; others are opaque, or discolored by the green carbonate of copper. Also in the trap rock between Fond du Lac and Old Grand Portage, Lake Superior, in perfect, transparent rhombs, exhibiting the property of double refraction. Also, at the lead mines, in Iowa county, in the marly clay formation, often exhibiting imperfect prisms, variously truncated.
2. Calcareous tufa. Mouth of the River Brulé, of Lake Superior. In small, friable, broken masses, in the diluvial soil. Also, in the gorge below the Falls of St. Anthony. In detached, vesicular masses, amidst debris.
3. Compact carbonate of lime. In the calcareous cliffs of horizontal formation, commencing at the Falls of St. Anthony. Carboniferous.
4. Septaria. In the reddish clay soil, between Montreal River, and Lapointe, Lake Superior.
5. Gypsum. In the sandstone rock at the Point of Grand Sable West, Lake Superior. In orbicular masses, firmly imbedded. Not abundant. Granular, also imperfectly foliated.
6. Carbonate of magnesia. Serpentine rock, at Presque Isle, Lake Superior. Compact.
7. Hydrate of magnesia? With the preceding.
CLASS II. Earthy compounds, amorphous or crystalline.
8. Common quartz. Huron Islands, Lake Superior, also the adjoining coast. In very large veins or beds. White, opaque.
9. Granular quartz. Falls of Peckagama, Upper Mississippi. In situ.