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.
There is very good marble, and in very great abundance, on James' river, at the mouth of Rockfish. The samples I have seen, were some of them of a white as pure as one might expect to find on the surface of the earth; but most of them were variegated with red, blue, and purple. None of it has been ever worked. It forms a very large precipice, which hangs over a navigable part of the river. It is said there is marble at Kentucky.
But one vein of limestone is known below the Blue Ridge. Its first appearance, in our country, is in Prince William, two miles below the Pignut ridge of mountains; thence it passes on nearly parallel with that, and crosses the Rivanna about five miles below it, where it is called the South-west ridge. It then crosses Hard-ware, above the mouth of Hudson's creek, James' river at the mouth of Rockfish, at the marble quarry before spoken of, probably runs up that river to where it appears again at Ross's iron-works, and so passes off south-westwardly by Flat Creek of Otter river. It is never more than one hundred yards wide. From the Blue Ridge westwardly, the whole country seems to be founded on a rock of limestone, besides infinite quantities on the surface, both loose and fixed. This is cut into beds, which range, as the mountains and sea-coast do, from south-west to north-east, the lamina of each bed declining from the horizon towards a parallelism with the axis of the earth. Being struck with this observation, I made, with a quadrant, a great number of trials on the angles of their declination, and found them to vary from 22° to 60°; but averaging all my trials, the result was within one-third of a degree of the elevation of the pole or latitude of the place, and much the greatest part of them taken separately were little different from that; by which it appears, that these lamina are, in the main, parallel with the axis of the earth. In some instances, indeed, I found them perpendicular, and even reclining the other way; but these were extremely rare, and always attended with signs of convulsion, or other circumstances of singularity, which admitted a possibility of removal from their original position. These trials were made between Madison's cave and the Potomac. We hear of limestone on the Mississippi and Ohio, and in all the mountainous country between the eastern and western waters, not on the mountains themselves, but occupying the valleys between them.
Near the eastern foot of the North mountain are immense bodies of Schist; containing impressions of shells in a variety of forms. I have received petrified shells of very different kinds from the first sources of Kentucky, which bear no resemblance to any I have ever seen on the tide-waters. It is said that shells are found in the Andes, in South America, fifteen thousand feet above the level of the ocean. This is considered by many, both of the learned and unlearned, as a proof of an universal deluge. To the many considerations opposing this opinion, the following may be added: The atmosphere, and all its contents, whether of water, air, or other matter, gravitate to the earth; that is to say, they have weight. Experience tells us, that the weight of all these together never exceeds that of a column of mercury of thirty-one inches height, which is equal to one of rain water of thirty-five feet high. If the whole contents of the atmosphere, then, were water, instead of what they are, it would cover the globe but thirty-five feet deep; but as these waters, as they fell, would run into the seas, the superficial measure of which is to that of the dry parts of the globe, as two to one, the seas would be raised only fifty-two and a half feet above their present level, and of course would overflow the lands to that height only. In Virginia this would be a very small proportion even of the champaign country, the banks of our tide-waters being frequently, if not generally, of a greater height. Deluges beyond this extent, then, as for instance, to the North mountain or to Kentucky, seem out of the laws of nature. But within it they may have taken place to a greater or less degree, in proportion to the combination of natural causes which may be supposed to have produced them. History renders probably some instances of a partial deluge in the country lying round the Mediterranean sea. It has been often[3] supposed, and it is not unlikely, that that sea was once a lake. While such, let us admit an extraordinary collection of the waters of the atmosphere from the other parts of the globe to have been discharged over that and the countries whose waters run into it. Or without supposing it a lake, admit such an extraordinary collection of the waters of the atmosphere, and an influx from the Atlantic ocean, forced by long-continued western winds. The lake, or that sea, may thus have been so raised as to overflow the low lands adjacent to it, as those of Egypt and Armenia, which, according to a tradition of the Egyptians and Hebrews, were overflowed about two thousand three hundred years before the Christian era; those of Attica, said to have been overflowed in the time of Ogyges, about five hundred years later; and those of Thessaly, in the time of Deucalion, still three hundred years posterior. But such deluges as these will not account for the shells found in the higher lands. A second opinion has been entertained, which is, that in times anterior to the records either of history or tradition, the bed of the ocean, the principal residence of the shelled tribe, has, by some great convulsion of nature, been heaved to the heights at which we now find shells and other marine animals. The favorers of this opinion do well to suppose the great events on which it rests to have taken place beyond all the eras of history; for within these, certainly, none such are to be found; and we may venture to say farther, that no fact has taken place, either in our own days, or in the thousands of years recorded in history, which proves the existence of any natural agents, within or without the bowels of the earth, of force sufficient to heave, to the height of fifteen thousand feet, such masses as the Andes. The difference between the power necessary to produce such an effect, and that which shuffled together the different parts of Calabria in our days, is so immense, that from the existence of the latter, we are not authorized to infer that of the former.
M. de Voltaire has suggested a third solution of this difficulty. (Quest. Encycl. Coquilles.) He cites an instance in Touraine, where, in the space of eighty years, a particular spot of earth had been twice metamorphosed into soft stone, which had become hard when employed in building. In this stone shells of various kinds were produced, discoverable at first only with a microscope, but afterwards growing with the stone. From this fact, I suppose, he would have us infer, that, besides the usual process for generating shells by the elaboration of earth and water in animal vessels, nature may have provided an equivalent operation, by passing the same materials through the pores of calcareous earths and stones; as we see calcareous drop-stones generating every day, by the percolation of water through limestone, and new marble forming in the quarries from which the old has been taken out. And it might be asked, whether is it more difficult for nature to shoot the calcareous juice into the form of a shell, than other juices into the forms of crystals, plants, animals, according to the construction of the vessels through which they pass? There is a wonder somewhere. Is it greatest on this branch of the dilemma; on that which supposes the existence of a power, of which we have no evidence in any other case; or on the first, which requires us to believe the creation of a body of water and its subsequent annihilation? The establishment of the instance, cited by M. de Voltaire, of the growth of shells unattached to animal bodies, would have been that of his theory. But he has not established it. He has not even left it on ground so respectable as to have rendered it an object of inquiry to the literati of his own country. Abandoning this fact, therefore, the three hypotheses are equally unsatisfactory; and we must be contented to acknowledge, that this great phenomenon is as yet unsolved. Ignorance is preferable to error; and he is less remote from the truth who believes nothing, than he who believes what is wrong.
There is great abundance (more especially when you approach the mountains) of stone, white, blue, brown, &c., fit for the chisel, good mill-stone, such also as stands the fire, and slate stone. We are told of flint, fit for gun-flints, on the Meherrin in Brunswick, on the Mississippi between the mouth of the Ohio and Kaskaskia, and on others of the western waters. Isinglass or mica is in several places; loadstone also; and an Asbestos of a ligneous texture, is sometimes to be met with.
Marle abounds generally. A clay, of which, like the Sturbridge in England, bricks are made, which will resist long the violent action of fire, has been found on Tuckahoe creek of James' river, and no doubt will be found in other places. Chalk is said to be in Botetourt and Bedford. In the latter county is some earth believed to be gypseous. Ochres are found in various parts.
In the lime-stone country are many caves, the earthy floors of which are impregnated with nitre. On Rich creek, a branch of the Great Kanhaway, about sixty miles below the lead mines, is a very large one, about twenty yards wide, and entering a hill a quarter or half a mile. The vault is of rock, from nine to fifteen or twenty feet above the floor. A Mr. Lynch, who gives me this account, undertook to extract the nitre. Besides a coat of the salt which had formed on the vault and floor, he found the earth highly impregnated to the depth of seven feet in some places, and generally of three, every bushel yielding on an average three pounds of nitre. Mr. Lynch having made about ten hundred pounds of the salt from it, consigned it to some others, who have since made ten thousand pounds. They have done this by pursuing the cave into the hill, never trying a second time the earth they have once exhausted, to see how far or soon it receives another impregnation. At least fifty of these caves are worked on the Greenbriar. There are many of them known on Cumberland river.