would come back and open into the sides or banks of the ravine, guided by the gold, and at last, discover valuable bodies of gold ore. Many instances of this kind are notorious in North Carolina and Virginia." The branch gold mines of the U. States, are supposed to have yielded 6,000,000 of dollars, most of which is worked up in jewellery, and not in coinage.

Three deposit mines in Georgia have yielded 500,000 dollars, and Mr. Taylor confidently anticipates that the gold deposits of the United States will yield far larger returns than those of Brazil, Colombia, and the Urals united.

The explorations for gold have not, as yet, been carried to a great depth, the greatest not exceeding one hundred and fifty feet, and few of the shafts are over one hundred feet, and most do not exceed twenty or thirty. These excavations are too shallow to afford satisfactory information respecting the gold, and the digging is often abandoned upon the slightest unfavorable appearance such as the narrowing of the vein, its dislocation, or its becoming shattered, for there is much appearance of disorganization in the veins and rocks. Pyritical ores constitute the mass of the ores in Columbia, the Brazils, and the United States; above the depth of one hundred feet, they have been, in this country, partially decomposed; the yellow ores have been converted into brown, red and purple hydrates of iron, and a portion of the gold they contain having thus become uncovered, is accessible to amalgamation, while a large portion more is, or can be developed by the assay by fire.

Most of the gold is extracted by amalgamation, after stamping under water, and the residuum still contains gold.

Messrs. Andres Del Rio and John Millington, as a committee from the Geological Society of Pennsylvania, have investigated the Rappahannock gold mines in Virginia, situated on the river, about ten miles from Fredericksburgh; the tract is about two hundred and thirty yards wide by an average length of upwards of nine hundred yards.

The metalliferous veins consist of hard quartzoze rock between walls of decomposed talcose slate. A portion of loose red soil by washing two handfuls of it gave a considerable quantity of minute granular gold, and similar results were obtained by washings in other places. A principal auriferous quartz vein is from two feet six inches to three feet six inches wide: it stands vertically between walls of talcose slate; there is also, on either side, a vertical bed of auri

ferous red earth from two to three and a half feet wide, and bounded also by talcose slate. The auriferous quartz vein has been exposed to view for six hundred and twenty seven feet with a width of thirty inches, and it would appear that this is only the beginning. By a rough process of washing, amalgamation and evaporation of the mercury, three and a half grains of gold were obtained from four pounds of the ore taken indiscriminately from all parts of the vein, and in another experiment five grains of gold were produced from four pounds of pure milk-white quartz, which had no appearance or indication of containing any metal at all.

Messrs. Del Rio and Millington think that each pound of the ore may be made to yield one grain of gold or five pennyweights to the one hundred pounds of ore; this would much more than pay the expense, which cannot exceed one dollar on one hundred pounds of the crude material. It appears that by heating the quartz red hot and throwing it into cold water, eight grains of gold were obtained from five pounds of ore. In the opinion of Mr. Dickson, the Rappahannock mines perfectly resemble all the others in Virginia. On the whole the gold region of the United States is very extensive, rich and promising, and there is every adventitious advantage of fuel, food, climate, cultivation and security.

We have seen a decisive experiment of this kind made upon white quartz from Virginia which yielded a considerable quantity of gold by simple pounding and washing without amalgamation.-Ed.

3. New Trilobite, &c.

DR. Jacob Green whose excellent monograph on the trilobites of this country, illustrated by beautiful plaster models is well known, has described in the Geological Transactions of Philadelphia, a new trilobite found by Dr. C. T. Jackson in Nova Scotia, in magnetic iron ore which is beautifully impressed by various organic bodies, among which the present trilobite, called by Dr. Green Asaphus crypturus is conspicuous. For the description and drawing we must refer to the Transactions.

Dr. Green has also given an account of the chemical examination of a sulphated ferruginous earth from Kent county, Delaware, with a view to ascertain its commercial value.

4. Fossil Zoology and Comparative Anatomy.

Dr. Harlan has communicated a good paper on the structure of the teeth in the Edentata, fossil and recent; and this is followed by a

critical notice of the various organic remains hitherto discovered in North America.

Of this very important paper it is difficult to give an analysis, as it is drawn up in a very condensed form, and will be read with much advantage by all those who are desirous of accurate information on this very interesting but imperfectly explored department of American Geology. In comparative anatomy and fossil zoology we have great need of zeal, science, and discriminating tact. On these subjects Dr. Harlan is justly regarded as a high authority, especially in facts relating to this country.

The great Mastodon. He justly remarks that “in most instances there is sufficient evidence that these animals died and left their bones to become fossilized in the precise situations in which they are now found; not only are the teeth and bones of this animal unworn by the action of running waters, but the skeleton is not unfrequently discovered in a standing position, just as the animal had sunk in the marsh or mud, clay and sand, and therefore that they have been destroyed subsequently to the action of those causes which formed the beds of gravel or detritus in and upon which they are frequently found." Dr. Harlan quotes from Baron Cuvier the remarkable fact furnished by the late Professor B. S. Barton, of the discovery in the remains of a Mastodon found in Withe county, Virginia, five and a half feet below the soil, of a kind of sack supposed to be the stomach of the animal, containing the identical substances which he had devoured, namely, semi-masticated small branches, grasses, leaves, &c. among which it was thought a species of brier, still common in Virginia, was recognizable. Cuvier remarks that he had rarely seen any remains of shells or zoophytes or the bones of the great mastodon, and therefore he infers that the sea had not long sojourned over them.

Dr. Harlan thinks that there is no evidence of the existence of the great mastodon, prior to the last general cataclysm, and that they may have disappeared, together with the fossil elk, or moose of Ireland, since the creation of man.

Mr. William Cooper of New York, who is also a high authority on subjects of Natural History, after a very full examination of many bones of the mastodon is of the opinion, that there is but one species among the great quantity of their bones found in the United States which have come under his observation.

Dr. Harlan remarks that the fossil bones of the elephant, although found with those of the mastodon, rhinoceros, megalonyx, ox, deer, &c., would appear to have belonged to a geological period more ancient than that of the last named animals, which, according to Cuvier, are dispersed every where, and often have marine animals attached to them, thus proving that they have been, for a considerable time, covered by the ocean.

Although there is an immense mass of the fossil bones of the elephant scattered through the world, there is only one perfect skeleton, namely, that in the museum of Petersburgh. It was found encased in an ice cliff on the shores of the Northern Ocean.

Bones of that very extraordinary animal, the megatherium, were found, some years ago, in Skidaway Island, Georgia, and described by the late Dr. Mitchill and Mr. Wm. Cooper; a complete skeleton was obtained in 1789, on the borders of the River Suaan in South America, and is now in the museum at Madrid. This animal has considerable resemblance to the sloth-it is of a gigantic size, the bones of the feet being more than a yard long by twelve inches wide. The bones of the megatherium are still to be obtained at the above named place in great quantity, by some labor and expense, and also at two other places in Georgia--the White Bluff on the Sea coast and some distance up the Savannah River.

The megalonyx is, in the opinion of Cuvier, allied to the megatherium, and as yet there are only three places known where the bones are found-Green Briar County, Va. and Big Bone lick and White. Cave, Ky. The bones sent to Philadelphia by the late President Jefferson, were from Green Briar County; they were found buried two or three feet deep in the saltpetre earth of a cavern, and are still in excellent preservation, completely fossilized and very dense and heavy.

The fossil Saurians promise to make a considerable figure in the geology of this country. Bones of a fossil crocodile and a vertebra of a plesiosaurus, have been found in the marl pits of New Jerseyand fragments supposed to be those of an Ichthyosaurus, near the Yellow Stone and Missouri Rivers. Teeth and probably a femur of the Mososaurus have been found in a marl pit near Woodbury, N. J., and a tooth and part of the jaw of the Geosaurus at Monmouth, N. J. A new genus, the Saurocephalus from Missouri, was described by Dr. Harlan about ten years since, (Jour. Acad. VOL. XXVII.-No. 2.

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Phil. Vol. III, p. 331, pl. xii.-1824); a distinct species of this genus discovered by Mr. Lea in a marl pit in New Jersey, was named by Dr. Hays, Saurocephalus Leanus, and he had also called it Saurodon.

Dr. Harlan has named a new Saurian Basilosaurus; it was found on the banks of the Washita or Ouachita river, Louisiana. (Amer. Philos. Trans., Vol. IV. New series, p. 297, pl. XX.-1834.

One of the vertebræ weighs forty four pounds, and is fourteen inches long by seven broad. Allowing the animal sixty six vertebræ, like the Plesiosaurus, Dr. Harlan estimates the weight of the skeleton as being over two tons, and that the individual must have been from eighty to one hundred feet in length. Its geological position was in the Atlantic tertiary. To the localities of fossil fish quoted from Professor Hitchcock, and cited by Dr. Harlan, we can add one at Southbury, Ct. twenty four miles north west of New Haven. We saw but a single specimen; it was from a bituminous shale in a basin of six or eight miles in diameter, of red sandstone, sustaining ridges of trap, and surrounded by primitive rocks.

5. Professor Del Rio's Critique on the Mineralogy of Mr. C. U. Shepard. Upon this subject we shall make no remarks, as Mr. Shepard has spoken for himself in the present number, in a distinct article.

Professor Rio's Observations on the conversion of sulphuret of silver into native silver may be read with advantage and instruction. 6. Notice of the gigantic mastodon, the elephant, and the megalonyx jeffersonii in Tennessee, by Professor G. Troost."

Numerous bones of the Mastodon were found about eleven miles south east of Nashville imbedded in a rich black mould, resting on a stiff ferruginous loam which the bones partly penetrated; the bones are in general pretty sound, and very heavy, being impregnated by hydrated oxide of iron. There were vertebræ of at least two individuals.

Another skeleton was found near the same place a few years ago about six feet under ground.

Dr. Troost has a tooth found near Dandridge in East Tennessee, and still another with a part of the jaw bone attached: this was from the vicinity of Natchez.

Molar teeth of the extinct elephant have been found in Tennessee. Bones, supposed to be those of the megalonyx, have been found in a salt-petre cave in Tennessee.