Читать книгу The Collected Works - Henry Rowe Schoolcraft - Страница 31

BY HENRY R. SCHOOLCRAFT.

CLASS I. Bodies not metallic, containing an acid.

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.

10. Smoky quartz. In the trap rock Keweena Point, Lake Superior, crystallized. In connection with amethystine quartz.

11. Amethyst. With the preceding. Also, at the Pic Bay, and at Gargontwa, north shore of Lake Superior, in the trap rock, in perfect crystals of various intensity of color.

12. Chalcedony. Keweena Point, Lake Superior. In globular or orbicular masses, in amygdaloid rock. Often, in detached masses along the shores.

13. Carnelian. With the preceding.

14. Hornstone. In detached masses, very hard, on the shores of Lake Superior. Also, at Dodgeville, Iowa county, Mich. Ter. in fragments or nodular masses in the clay soil.

15. Jasper. In the preceding locality. Common and striped, exceedingly difficult of being acted on, by the wheel. Not observed in situ.

16. Agate. Imbedded in the trap rocks of Lake Superior, and also detached, forming a constituent of its detritus. Variously colored. Often made up of alternate layers of chalcedony, carnelian, and cacholong. Sometimes zoned, or in fortification points. Specimens not taken from the rock are not capable of being scratched by quartz or flint, and are incapable of being acted on by the file; consequently harder than any of the described species.

17. Cyanite. Specimens of this mineral, in flat, six-sided prisms imbedded in a dark primitive rock, were brought out from Lac du Flambeau outlet, where the rock is described as existing in situ. The locality has not been visited, but there are facts brought to light within the last two or three years, to justify the extension of the primitive to that section of country.

18. Pitchstone. A detached mass of this mineral, very black and lava-like, was picked up in the region of Lake Superior, where the volcanic mineral, trachyte, is common among the rolled masses. Neither of these substances have been observed in situ.

19. Mica. Huron Islands, Lake Superior. In granite.

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.

30. Serpentine, precious. With the preceding. Color a light pistachio green, and takes a fine polish. Exists in veins in the common variety.

31. Pseudomorphous serpentine. With the preceding. This beautiful green mineral constitutes a portion of the veins of the precious serpentine. Its crystalline impressions are very distinct.

32. Argillite. River St. Louis, northwest of Lake Superior. Nearly vertical in its position.

CLASS III. Combustibles.

33. Peat. Marine sand formation composing the shore of Lake Superior, between White-fish Point and Grand Marrais. Also, on the island of Michilimackinac.

CLASS IV. Ores and Metals.

34. Native copper. West side of Keweena Point, Lake Superior. Imbedded in a vein with carbonate of copper, and copper black, in the trap rock.

35. Copper black. With the preceding.

36. Carbonate of copper, green. With the preceding.

These two minerals (35 and 36) characterize the trap rock of the peninsula of Keweena, Lake Superior, from Montreal Bay, extending to, and around its extremity, west, to Sand-hill Bay. The entire area may be estimated to comprise a rocky, serrated coast of about seventy-five miles in length, and not to exceed seven or eight miles in width. The principal veins are at a point called Roche Verd, and along the coast which we refer to as the Black Rocks. At the latter, native copper is one of the constituents of the vein.

Green and blue carbonate of copper, was also observed in limited quantity, in small rounded masses at one of the lead diggings near Mineral Point, Iowa county.

38. Chromate of iron. Presque Isle, Lake Superior.

39. Sulphuret of lead. Lead mines of Iowa county, Michigan Territory.

40. Earthy carbonate of lead. Brigham’s mine, Iowa county, Mich. Ter. Also, in small masses, of a yellowish white, dirty color, and great comparative weight, at several of the lead mines (diggings) in the more westerly and southern parts of the county.