39. Sulphuret of Lead.
a. Galena. One of the most remarkable formations of this ore in America, if not in the world, is furnished by the metalliferous limestones of the Mississippi. Of these, Missouri furnishes one of the most celebrated localities. These mines were first explored by the renowned Mississippi Company, in 1719, and have continued to be worked during the successive changes which it has experienced under the French, Spanish, and Americans, to the present period. The number of mines now wrought is about fifty, and the quantity of lead annually smelted is estimated at three millions of pounds. The ore is the common galena, with a broad glittering grain, and bluish-gray color, and is found accompanied by sulphate of barytes, blende, pyrites, quartz, and calcareous spar. It yields, on assay, eighty-two per cent. of metallic lead, the remainder being chiefly sulphur. (Vide "View of the Lead-Mines.")
b. Granular Sulphuret of Lead. Mine La Motte, Madison county, Missouri.
c. Cobaltic Sulphuret of Lead. With the preceding.
40. Oxide of Lead. Earthy, yellow. Wythe county, Virginia.
41. Carbonate of Lead. Lead-mines of Missouri. It occurs in some of the mines as a crust, or thin layer, on ores of galena.
42. Sulphuret of Zinc. In the form of black blende. Lead-mines of Missouri.
43. Oxide of Zinc. Earthy, grayish-white. In the mineral called "dry-bone." Missouri lead-mines.
44. Iron.
a. Iron Glance. In the Iron Mountain and Pilot Knob, on the sources of the river St. Francis, Missouri. It occurs in vast masses, granular, and sometimes specular, without iridescence. Also, on White river, Arkansas.