But a constant issue of air, only varying in its force as the weather is drier or damper, will require a new hypothesis. There is another blowing cave in the Cumberland mountain, about a mile from where it crosses the Carolina line. All we know of this is, that it is not constant, and that a fountain of water issues from it.

The Natural Bridge, the most sublime of nature's works, though not comprehended under the present head, must not be pretermitted. It is on the ascent of a hill, which seems to have been cloven through its length by some great convulsion. The fissure, just at the bridge, is, by some admeasurements, two hundred and seventy feet deep, by others only two hundred and five. It is about forty-five feet wide at the bottom and ninety feet at the top; this of course determines the length of the bridge, and its height from the water. Its breadth in the middle is about sixty feet, but more at the ends, and the thickness of the mass, at the summit of the arch, about forty feet. A part of this thickness is constituted by a coat of earth, which gives growth to many large trees, The residue, with the hill on both sides, is one solid rock of lime-stone. The arch approaches the semi-elliptical form; but the larger axis of the ellipsis, which would be the cord of the arch, is many times longer than the transverse. Though the sides of this bridge are provided in some parts with a parapet of fixed rocks, yet few men have resolution to walk to them, and look over into the abyss. You involuntarily fall on your hands and feet, creep to the parapet, and peep over it. Looking down from this height about a minute, gave me a violent head-ache. If the view from the top be painful and intolerable, that from below is delightful in an equal extreme. It is impossible for the emotions arising from the sublime to be felt beyond what they are here; so beautiful an arch, so elevated, so light, and springing as it were up to heaven! the rapture of the spectator is really indescribable! The fissure continuing narrow, deep, and straight, for a considerable distance above and below the bridge, opens a short but very pleasing view of the North mountain on one side and the Blue Ridge on the other, at the distance each of them of about five miles. This

bridge is in the county of Rockbridge, to which it has given. name, and affords a public and commodious passage over a valley which cannot be crossed elsewhere for a considerable disThe stream passing under it is called Cedar-creek. It is a water of James' river, and sufficient in the driest seasons to turn a grist-mill, though its fountain is not more than two miles above.*

QUERY VI.

A notice of the mines and other subterraneous riches; its trees, plants, fruits, &c.

I knew a single instance of gold found in this State. It was interspersed in small specks through a lump of ore of about four

*Don Ulloa mentions a break, similar to this, in the province of Angaraez, in South America. It is from sixteen to twenty-two feet wide, one hundred and eleven feet deep, and of 1.3 miles continuance, English measure. Its breadth at top is not sensibly greater than at bottom. But the following fact is remarkable, and will furnish some light for conjecturing the probable origin of our natural bridge. 'Esta caxa, ó cauce está cortada en péna viva con tanta precision, que las desigualdades del un lado entrantes, corresponden a las del otro lado salientes, como si aquella altura se hubiese abierto expresameute, con sus bueltas y tortuosidades, para darle transito á los aguas por entre los dos morallones que la forman; siendo tal su igualdad, que si llegasen á juntarse se endentarian uno con otro sin dextar hueco." Not. Amer. ii. § 10. Don Ulloa inclines to the opinion that this channel has been effected by the wearing of the water which runs through it, rather than that the mountain should have been broken open by any convulsion of nature. But if it had been worn by the running of water, would not the rocks which form the sides, have been worn plain? or if, meeting in some parts with veins of harder stone, the water had left prominences on the one side, would not the same cause have sometimes, or perhaps generally, occasioned prominences on the other side also? Yet Don Ulloa tells us, that on the other side there are always corresponding cavities, and that these tally with the prominences so perfectly, that, were the two sides to come together they would fit in all their indentures, without leaving any void. I think that this does not resemble the effect of running water, but looks rather as if the two sides had parted asunder. The sides of the break, over which is the natural bridge of Virginia, consisting of a veiny rock which yields to time, the correspondence between the salient and re-entering inequalities, if it existed at all, has now disappeared. This break has the advantage of the one described by Don Ulloa in its finest circumstance; no portion in that instance having held together, during the separation of the other parts, so as to form a bridge over the abyss.

pounds weight, which yielded seventeen pennyweights of gold, of extraordinary ductility. This ore was found on the north side of Rappahanoc, about four miles below the falls. I never heard of any other indication of gold in its neighborhood.

On the Great Kanhaway, opposite to the mouth of Cripple creek, and about twenty-five miles from our southern boundary, in the county of Montgomery, are mines of lead. The metal is mixed, sometimes with earth, and sometimes with rock, which requires the force of gunpowder to open it; and is accompanied with a portion of silver too small to be worth separation under any process hitherto attempted there. The proportion yielded is from fifty to eighty pounds of pure metal from one hundred pounds of washed ore. The most common is that of sixty to one hundred pounds. The veins are sometimes most flattering, at others they disappear suddenly and totally. They enter the side of the hill and proceed horizontally. Two of them are wrought at present by the public, the best of which is one hundred yards under the hill. These would employ about fifty laborers to advantage. We have not, however, more than thirty generally, and these cultivate their own corn. They have produced sixty tons of lead in the year; but the general quantity is from twenty to twenty-five tons. The present furnace is a mile from the ore bank and on the opposite side of the river. The ore is first wagoned to the river, a quarter of a mile, then laden on board of canoes and carried across the river, which is there about two hundred yards wide, and then again taken into wagons and carried to the furnace. This mode was originally adopted that they might avail themselves of a good situation on a creek for a pounding mill; but it would be easy to have the furnace and pounding mill on the same side of the river, which would yield water, without any dam, by a canal of about half a mile in length. From the furnace the lead is transported one hundred and thirty miles along a good road, leading through the peaks of Otter to Lynch's ferry, or Winston's on James' river, from whence it is carried by water about the same distance to Westham. This land carriage may be greatly shortened, by delivering the lead on James' river, above the Blue Ridge, from

whence a ton weight has been brought on two canoes. The Great Kanhaway has considerable falls in the neighborhood of the mines. About seven miles below are three falls, of three or four feet perpendicular each; and three miles above is a rapid of three miles continuance, which has been compared in its descent to the great falls of James' river. Yet it is the opinion, that they may be laid open for useful navigation, so as to reduce very much the portage between the Kanhaway and James' river.

A valuable lead mine is said to have been lately discovered in Cumberland, below the mouth of Red river. The greatest, however, known in the western country, are on the Mississippi, extending from the mouth of Rock river one hundred and fifty miles upwards. These are not wrought, the lead used in that country being from the banks on the Spanish side of the Mississippi, opposite to Kaskaskia.

A mine of copper was once opened in the county of Amherst, on the north side of James' river, and another in the opposite country, on the south side. However, either from bad management or the poverty of the veins, they were discontinued. We are told of a rich mine of native copper on the Ouabache, below the upper Wiaw.

The mines of iron worked at present are Callaway's, Ross's, and Ballendine's, on the south side of Janies' river; Old's on the north side, in Albemarle; Miller's in Augusta, and Zane's in Frederic. These two last are in the valley between the Blue Ridge and North mountain. Callaway's, Ross's, Miller's, and Zane's make about one hundred and fifty tons of bar iron each, in the year. Ross's makes also about sixteen hundred tons of pig iron annually; Ballendine's one thousand; Callaway's, Miller's, and Zane's, about six hundred each. Besides these, a forge of Mr. Hunter's, at Fredericksburg, makes about three hundred tons a year of bar iron, from pigs imported from Maryland; and Taylor's forge on Neapsco of Potomac, works in the same way, but to what extent I am not informed. The indications of iron in other places are numerous, and dispersed through all the middle country. The toughness of the cast iron of Ross's

and Zane's furnaces is very remarkable. Pots and other utensils, cast thinner than usual, of this iron, may be safely thrown into, or out of the wagons in which they are transported. Saltpans made of the same, and no longer wanted for that purpose, cannot be broken up, in order to be melted again, unless previously drilled in many parts.

In the western country, we are told of iron mines between the Muskingum and Ohio; of others on Kentucky, between the Cumberland and Barren rivers, between Cumberland and Tennessee, on Reedy creek, near the Long Island, and on Chesnut creek, a branch of the Great Kanhaway, near where it crosses the Carolina line. What are called the iron banks, on the Mississippi, are believed, by a good judge, to have no iron in them. In general, from what is hitherto known of that country, it seems to want iron.

Considerable quantities of black lead are taken occasionally for use from Winterham in the county of Amelia. I am not able, however, to give a particular state of the mine. There is no work established at it; those who want, going and procuring it for themselves.

The country on James' river, from fifteen to twenty miles above Richmond, and for several miles northward and southward, is replete with mineral coal of a very excellent quality. Being in the hands of many proprietors, pits have been opened, and, before the interruption of our commerce, were worked to an extent equal to the demand.

In the western country coal is known to be in so many places, as to have induced an opinion, that the whole tract between the Laurel mountain, Mississippi, and Ohio, yields coal. It is also known in many places on the north side of the Ohio. The coal at Pittsburg is of very superior quality. A bed of it at that place has been a-fire since the year 1765. Another coal-hill on the Pike-run of Monongahela has been a-fire ten years; yet it has burnt away about twenty yards only.

I have known one instance of an emerald found in this country. Amethysts have been frequent, and crystals common; yet not in such numbers any of them as to be worth seeking.