a. Calc. Spar. This form of the carbonate of lime is common in the lead-mine regions of Missouri. At Hazel run, it constitutes, to some extent, the gangue of the lead-ores. It is generally imbedded in lumps in the red clay mineral soil. These lumps are round, externally; but, on being broken, reveal a rhomboidal structure, and are beautifully transparent.
b. Stalactites. This form of the carbonate of lime is found in a cave on the head-waters of Currents river, in Missouri. The stalactites are found in concretions resembling icicles hanging from the roof, or in columns reaching to the floor. The specimens are translucent. Stalactites are also found in a very large cave (Winoca) on Findley's fork, one of the tributaries of White river, Arkansas. They form two large vases in this cave, which are filled with the most crystalline water.
c. Stalagmite (Calcareous Alabaster). The cave which has just been mentioned on Findley's fork, affords this mineral in small, solid globules, which strew the floor of the cave.
5. Fluor Spar. The elevated lands on the west banks of the Ohio, near the picturesque shores of Cave-in-Rock, in Illinois, disclose this mineral. It exhibits its well-known character. It is generally of a purple, or amethystine hue, and crystallized, as its primary form, in cubes. Externally, these crystals are dull. Its association here is with the ores of lead, which have been extensively searched for in former times. It is plentifully found, sometimes in large crystals, which have an external appearance as if they had been subjected to the influence of turbid water. It has been thus far, chiefly, explored in the diluvial stratum.
6. Gypsum. Foliated masses of this mineral occur in the river cliffs in St. Clair county, Illinois. It is found in large quantities near the salines in Upper Arkansas. Dr. Sibley, speaking of the formation in that vicinity, says: "It is a tract of about seventy-five miles square, in which nature has arranged a variety of the most strange and whimsical vagaries. It is an assemblage of beautiful meadows, verdant ridges, and rude misshapen piles of red clay, thrown together in the utmost apparent confusion, yet affording the most pleasing harmonies, and presenting in every direction an endless variety of curious and interesting objects. After winding along for a few miles on the high ridges, you suddenly descend an almost perpendicular declivity of rocks and clay, into a series of level and fertile meadows, watered by some beautiful rivulets, and adorned here and there with shrubby cotton trees, elms, and cedars. These meadows are divided by chains formed of red clay, and huge masses of gypsum, with here and there a pyramid of gravel. One might imagine himself surrounded by the ruins of some ancient city, and that the plain had sunk by some convulsion of nature more than one hundred feet below its former level; for some of the huge columns of red clay rise to the height of two hundred feet perpendicular, capped with rocks of gypsum, which the hand of time is ever crumbling off, and strewing in beautiful transparent flakes, along the declivities of the hill, glittering like so many mirrors in the sun."
7. Sulphate of Magnesia. A large and curious cavern has been discovered in the calcareous rocks at Corydon, near the seat of government of Indiana, which is found to yield very beautiful white crystals of this mineral. To what extent these appearances exist, is unknown; but the cavern invites exploration.
8. Alum. Efflorescences of the sulphate of alumina exist in a calcareous cavern in the elevated ranges of Bellevieu, in the county of Washington, Mo. No practical use is made of it.
9. Quartz. This important family of mineral bodies exists, in many of its forms, on the west banks of the Mississippi. They will be noticed under their appropriate names.
a. Granular Quartz. There is a very large body of this mineral about eight miles west of St. Genevieve, near the Potosi road. It is known as the site of a remarkable cave. The sides, roof, and floor of the cave, consist of the most pure and white granular quartz. It is quite friable between the fingers, and falls into a singularly transparent and beautiful sand. Each of these grains, when examined by the microscope, is found to be a transparent molecule of pure quartz. It possesses no definable tint of color, is not acted upon by either nitric or muriatic acids, and appears to be an aggregation of minute crystals of quartz. It occurs in several caves near the road, whose sides are entirely composed of it; and its snowy hue, and granular structure, give it the appearance of refined sugar. It appears to me to be composed of silex nearly or quite pure, and possesses, as I find on treatment with potash, the property of easy fusibility. Could the necessary alkali and apyrous clays be conveniently had at this spot, I cannot conceive a more advantageous place for a manufactory of crystal glass.
b. Radiated Quartz. This mineral is found in great abundance at the Missouri lead-mines, where it bears the striking name of mineral blossom, or blossom of lead—an opinion being entertained that it indicates the presence or contiguity of lead-ore. Examined with care, it is found to consist of small crystals of quartz, disposed in radii, which resemble the petals of a flower. These crystals are superimposed on a basis consisting of thin lines, or tabular layers, of agate. It is found either strewn on the surface of the soil, imbedded in it, or existing in cavities in the limestone rock.