n. Hoary Quartz. West banks of the Mississippi, Mo. The character of hoariness appears to be imparted by very minute crystals, or concretions of quartz, on the surface of radiated quartz.
o. Common Quartz. This mineral is found in veins of from one to eight or ten feet wide, in the argillaceous rock formation in the vicinity of the Hot Springs of Washita. It is also seen, in very large detached masses, on the south bank of White river. The character of these rocks will not be recognized on a superficial view; for they have a gray, time-worn appearance, and are so much covered by moss, that it was not until I had broken off a fragment with a hammer, that I discovered them to be white quartz. Pebbles of quartz, either white or variously colored by iron, are common on the shores of White river, and, joined to the purity and transparency of the waters, add greatly to the pleasure of a voyage on that beautiful stream.
p. Buhrstone. Raccoon creek, Indiana. This bed is noted throughout the western country, and affords a profitable branch of manufacture. It covers an area of from ten to fifteen acres square. Its texture is vesicular, yet it is sufficiently compact to admit of being quarried with advantage, and the stones are applied to the purposes of milling with the best success.
q. Sedimentary Quartz—Schoolcraftite. This mineral occurs three miles from the Hot Springs of Washita. It is of a grayish-white color, partaking a little of green, yellow, or red; translucent in an uncommon degree, with an uneven and moderately glimmering fracture, and susceptible of being scratched with a knife. Oil stones for the purpose of honing knives, razors, or tools, are occasionally procured from this place, and considerable quantities have been lately taken to New Orleans. It gives a fine edge, and is considered equal to the Turkish oil-stone. It appears to me, from external character and preliminary tests, to consist almost entirely of silex, with a little oxide of iron. Its compactness, superior softness, specific gravity, and coloring matter, distinguish it from silicious sinter. It has been improperly termed, heretofore, "novaculite." It contains no alumine. It sometimes reveals partial conditions, or spots, of a degree of hardness nearly equal to common quartz.
r. Carnelian. Banks of the Mississippi, above the junction of the Ohio. Traces of this mineral begin to be found, as soon as the heavy alluvial lands are passed. It is among the finest detritus of the minerals of the quartz family, brought down from upper plains. The fragments, in these lower positions, are small, transparent, and hard, colored red or yellowish.
s. Basanite—Touchstone. This mineral is found in the Mississippi detritus; but no fixed locality has been ascertained.
10. Pumice. The light, vesicular substance, found floating down the Missouri and Mississippi, is not, properly speaking, a true pumice, capable of the applications of that article in the arts; but it cannot be classified with any other species. It is more properly a pseudo-pumice, arising from partial volcanic action on the formations of some of the tributaries of the Missouri, which originate in the Rocky mountains. It is brought down by the June flood, sometimes in large masses, which, as the waters abate, are left on the islands or shores. It is incompletely vitrified, consisting of spongy globules. The masses are irregularly colored, agreeably to the vitrified materials, red, black or brown. Its tenacity is very great.
30. Mica. In the granitical, or primitive district, at the sources of the St. Francis. The great body of these rocks is a sienite, or sienitic granite, or greenstone. Like the northern granitical tracts, the mica is generally replaced by hornblende. The folia, usually, are small.
31. Feldspar. With the preceding. The great bulk of these granitical formations consists of red feldspar. Where the greenstone becomes porphyritic, the feldspar is a light green.
32. Hornblende. With the preceding. This mineral assumes its crystalline form, in large areas of the sienite rock. With the two preceding minerals, mica and feldspar, and common quartz, it constitutes the mountain peaks of that remarkable district. It is the only locality, except the Washita hills, where these formations rise to an elevation above the great metalliferous sandstone, and carbonaceous deposits of the central area of the Mississippi valley, south of the Sauk rapids, above St. Anthony's falls, and the head-waters of the St. Peter's, or Minnesota river. The latter constitute the northern limits of the great horizontal, sedimentary, semi-crystallized rocks west of the Alleghanies.