Graphite or plumbago, commonly but improperly called black lead, occurs extensively in primitive and transition rocks; from that which is obtained in New York, excellent pencils have been made. There are also numerous localities of petroleum, or mineral oil. It usually floats on the surface of springs, which in many cases are known to be in the vicinity of coal. It is sometimes called Seneca or Gennessee oil. In Kentucky, it occurs on a spring of water in a state sufficiently liquid to burn in a lamp; it is collected in considerable quantities.
Salt appears to be abundant in the United States, but it has not been found in the mass. It is principally obtained from the springs which have been noticed in another part of the work. Professor Eaton has suggested doubts whether masses of salt really exist. He conceives that an apparatus for the spontaneous manufacture of salt may be found within the bosom of the earth, in those rocks which contain the necessary elements, and in this opinion he is supported by experiment. Subsequently, however, Mr. Eaton had reason to think that salt has existed in a solid state in cubical crystals, the hollow forms of which he discovered abundantly in the lias and saline rocks of the west, and it seems still to be highly probable that masses of salt exist in the neighborhood of the salt springs. The brine contains, besides the muriate of soda, a considerable proportion of muriate of lime and magnesia. Recently, also, bromine has been detected in the brine of salina, by Dr. Silliman. Saltpetre is abundant in the west, being found in numberless caves along the Missouri; and the shores of the Arkansas are almost covered with nitre. The testimony of Mr. Schoolcraft, in relation to the recent formation of quartz crystals, is very striking. They have been found, it appears, upon the handle of a spade, and the edge of some old shoes, which had been left for some years in an abandoned lead mine of the Shawnee Mountains. Crystals of great beauty and dimensions have been found in numerous localities. Many minerals which are rare in Europe, are found abundantly, and often in finer forms, in the United States; some, which have subsequently been detected elsewhere, were first discovered here, and not a few may still be claimed as the peculiar treasure of our country.
GENERAL REMARKS ON MINERALS.
It is observed by Dr. Mead, that a general resemblance can be traced between the minerals of North America, and those which have been found in the north of Europe, particularly in Norway and Sweden. This resemblance is stated to exist, not merely in the properties of the minerals themselves, but in the geological character, and geognostic situation throughout the whole series. It is observed more particularly in those specimens which are found to accompany the primitive formation at Arendal, in Norway;it is not confined, however, to the primitive range of mountains alone, as the same resemblance can be frequently traced, on comparing American minerals with those of Piedmont, and even of the Hartz Mountains. Among the principal minerals of the north of Europe, there are none of more importance than the ores of iron for which Norway and Sweden are so remarkable; and every variety of this mineral which has been met with there, has been found in the same class of rocks in America in the greatest abundance, and of equally good quality. Titanium is one of those metals which have been found more particularly in the north of Europe. It is said to occur frequently in those primitive aggregates which contain beds of magnetic iron ore, associated with augite, scapolite, epidote and hornblende, precisely the same rocks in which we find it in this country. There is scarcely any part of Europe where a greater variety of augites are found than in Norway and Sweden; nor can there be any class of minerals in which the similitude between the specimens from those countries and America is more striking.
Mineralogy, considered as a pure science, is of very recent date. Early observations related merely to the usefulness of minerals to the purposes of society, and it was not before the lapse of many ages that they came to be investigated on account of their great variety, and the beautiful arrangements of which they are susceptible. No attempt was made to classify them before the introduction of alchemy into Europe by the Arabians; and to Avicenna belongs the merit of the first arrangement. He divided minerals into stones, metals, sulphurous fossils, and salts. In 1774, Werner published his great work on the External Properties of Minerals, which was of eminent service in first calling the attention of naturalists to the only correct method of arriving at a knowledge of this department of nature. The study of minerals has received considerable attention during the last twenty years in the United States.
CHAPTER XVI.—ANIMALS.
I. QUADRUPEDS.
The Black Bear (ursus Americanus) is found in considerable numbers in the northern districts of America. In size and form he approaches nearest to the Brown Bear; but his color is a uniform shining jet black, except on the muzzle, where it is fawn colored; on the lips and sides of the mouth it is almost gray. The hair, except on the muzzle, is long and straight, and is less shaggy than in most other species. The forehead has a slight elevation, and the muzzle is elongated, and somewhat flattened above. The young ones, however, are first of a bright ash color, which gradually changes into a deep brown, and ends by becoming a deep black.
