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