The Nottoway and Meherrin rivers drain a large part of the country south of the James River, each of them running about 100 miles, and uniting, after having entered North Caroliva, to form the Chowan Ricer.
The upper course of tbo Roanoke lies within Virginia. [CAROLINA, Nowrn.] It is navigable in Virginia below Monroe. Its largest affluent, the Dan, belongs almost entirely to Virginia; it drains the most southern portion of the Atlantic Slope, and is navigable for boats as far as Danville.
The Ohio divides Virginia from the state of Ohio, having between these two states a course of 355 miles. It is navigable all this distance for steamers of light draught. [MISSISSIPPI RIVER.] The Monongahela, one of the principal branches of the Ohio, is also noticed under Mrestestme RIVER. It is formed by three rivers, Cheat River, Tygart's Valley River, and West Fork, which rise in the Allegheny Mountains, and though not of much use for navigation, are of great value for the abundant water-power which they furnish. The Monongahela affords an easy navigation for steam-boats as far as Morgantown, about 10 miles from the boundary of Pennsylvania. The Little Kanawha, which joins the Ohio at Parkersburg, runs more than 100 miles, and with its principal effluent, Hughes River, is much used for bringing down lumber, &c. The Great Kanawha rises beyond Virginia, in the • valley inclosed by the Blue Ridge and the Iron Mountains; it traverses the mountain region by a course of 120 miles, and is swelled by the confluence of its great branch, the Greenbrier River. After it leaves the mountain region its rapidity is so great that as far down as the mouth of Gauley River the stream flows between high rocks with such force as to render crossing it very hazardous. Two miles below that place are the Groat Fall., a fine cataract of 22 feet over a natural dam of rocks which spreads irregularly across its bed. Below this place it becomes navigable, and from Charleston, 60 miles above its confluence with the Ohio, it is navigable for largo steam-boats. Its affluents, the Elk River, which joins it at Charleston, and the Coal River, which joins it 12 miles lower down, are navigable during freshets for a considerable distance. The Guyaudotte and the Big Sandy River, both of which flow above 100 mile.; are chiefly valuable for their immense water power.
The most southern portion of the mountain region is drained by several rivers, which by their junction, which takes place in the state of Tennessee, form the Tennessee River. These rivers are called, from cast to west, Holaton, Clinch, and Powell's. They are the only rivers that drain the mountain region which are navigable in their natural state.
The canals of Virginia are very important and costly works. They are—the Alexandrian Canal, from Georgetown to Alexandria, 71 miles ; James River and Kanawha Canal, which is completed from Rich mond to Balcony Fall; 148 miles, but is eventually to be carried along the valley of the Kanawha to the Ohio; Dismal Swamp Canal, from Deep Creek to Joyce's Creek, 23 mike; and 11 miles of branch canals; total 1891 miles.
The railways of this state are also on a very grand scale, being parts of the great lines which extend from the Atlantic to the West, and are connected wIth all the main lines of the neighbouring states. On the 1st of January 1855 there were in Virginia 23 lines of railways having 837 miles of road in operation; and 1095 miles additional were in course of construction or projected.
Geology, Mineralogy, eta—The geology of Virginia hse engaged much attention, and been illustrated in the writings of many of the most eminent geologists of Europe and America. By far the larger part of it belongs to the Allegheny system, and is sufficiently described under ALLEGIIANT MOUNTAINS. Here it will be enough to say that eruptive and metamorphic rocks traverse the state in a north-east and south-west direction, corresponding with that of the Allegheny range; and consist of granites, syenites, porphyries, gneiss, traps, &c. On the west of these igneous rocks, also traversing the state in the same direction, occur Lower Silurian strata, having a depth of 3000 feet, and consisting of limestones and sandstoues. These are skirted by a broader band of Upper Silurian rocks, comprising three or four varie ties of gray and blue limestones. Beyond these are beds of Devonian rocks, consisting of limestones crowned by vast beds of very thick old rod-sandstones. West of the Devoniau rocks we come upon the Carboniferous formation. The lower carboniferous strata occupy only a narrow belt, and are chiefly represented by red schist and siliceous conglomerates. But the upper carboniferous or coal-measures occupy the whole western side of the state, and form a portion of the great coal-basin of Ohio, Pennsylvania, and Virginia. New Red-sandstone occurs in small basins, whose general direction is parallel to the dislo cation of the Alleghenies. Strata of Ibis also occur in a band of from 10 to 12 miles wide, and about 50 miles long, extending from Rich mond to the neighbourhood of Washington ; they are inclosed in a deep and narrow granitic furrow, and consist "of a coarse-grained sandstone, formed from the decomposition of the surrounding granite, a species of micaceous schist, often very clayey, and passing into black slate; and lastly, beds of coal placed chiefly at the lower part of the formation, 40 or 50 feet in thickness." The whole eastern side of the state consists of Eocene and Posteeocene strata. The post eocene strata have a profusion of characteristic fossils, and Sir Charles Lyell assimilates them in age to the English crag and the faluns of Touraine.