scription of the section at p. 92. Vol. I., the strata at the same time becoming more and more horizontal. At the town of Union, which may be said to lie at the western foot of the mountains, I had an opportunity of seeing coal exposed to view in an open quarry of building stone. The coal seam was three and a half feet thick, with an intervening layer, as usual, between it and the freestone of dark slate or shale, four feet thick. When traced farther, the shale thinned out gradually, and in a neighbouring quarry, about thirty yards distant, it gave place to the yellow micaceous sandstone, which then formed the roof of the coal. These sandstone roofs are comparatively rare in America, as in Europe. From Union, we went to Brownsville on the Monongahela, a large tributary of the Ohio, where the country consists of coal measures, like those at Union, both evidently belonging to the same series as those more bent and curved beds at Frostburg before described. I was truly astonished, now that I had entered the hydrographical basin of the Ohio, at beholding the richness of the seams of coal, which appear everywhere on the flanks of the hills and at the bottom of the valleys, and which are accessible in a degree I never witnessed elsewhere. The time has not yet arrived, the soil being still densely covered with the primeval forest, and manufacturing industry in its infancy, when the full value of this inexhaustible supply of cheap fuel can be appreciated; but the resources which it will one day afford to a region capable, by its agricultural produce alone, of supporting a large population, are truly magnificent. In order to estimate the natural advantages of such a region, we must reflect how three great navigable rivers, such as the Monongahela, Alleghany, and Ohio, intersect it, and lay open on their banks the level seams of coal. I found at Brownsville a bed ten feet thick of good bituminous coal, commonly called the Pittsburg seam, breaking out in the river cliffs near the water's edge. I made a hasty sketch of its appearance from the bridge, looking down the river, in which the reader will see (a, Pl. VI.) the coal, ten feet thick, covered by carbonaceous shale (b), and this again by micaceous sandstone (c). Horizontal galleries may be driven everywhere at very slight expense, and so worked as to drain themselves, while the cars, laden with coal and attached to each other, glide down, as shown in the plate, on a railway, so as to deliver their burden into barges moored to the river's bank. The same seam is seen at a distance, on the right bank (at a), and may be followed the whole way to Pittsburg, fifty miles distant. As it is nearly horizontal, while the river descends it C 2 crops out at a continually increasing, but never at an inconvenient, height above the Monongahela. Below the great bed of coal at Brownsville is a fireclay eighteen inches thick, and, below this, several beds of limestone, below which again are other coal seams. I have also shown in my sketch another layer of workable coal (at d, d), which breaks out on the slope of the hills at a greater height. Almost every proprietor can open a coal-pit on his own land, and, the stratification being very regular, they may calculate with precision the depth at which the coal may be won. So great are the facilities of procuring this excellent fuel, that already it is found profitable to convey it in flat-bottomed boats for the use of steamships at New Orleans, 1100 miles distant, in spite of the dense forests bordering the intermediate riverplains, where timber may be obtained at the cost of felling it. But no idea can be formed of the importance of these American coal-seams, until we reflect on the prodigious area over which they are continuous. The boundaries of the Pittsburg seam have been determined with considerable accuracy by the Professors Rogers in Pennsylvania, Virginia, and Ohio, and they have found the elliptical area which it occupies to be 225 miles in its longest diameter, while its maximum breadth is about one hundred |