So late as 1860 the improved systems of mining, long in use in the North, were still comparatively unknown at the Virginia mines. During the war of the rebellion these mines were seized by the Confederate government and operated by it, in order to obtain directly the necessary fuel for purposes of modern warfare; and upon the cessation of hostilities the paralysis which had fallen upon all other Southern industries fell also upon this. But with the revival of business, mining was again begun in the Richmond field, and from 1874 to the present time the industry has prospered and grown, and Virginia has furnished to the country at large a considerable amount of an excellent quality of bituminous coal. This coal bed covers an area of about 180 square miles, and has an average thickness of twenty-four feet. It is supposed to contain about 50,000,000 of tons yet unmined. Another of the early discoveries of coal in the United States was that of the Rhode Island anthracite bed in 1760. Mines began to be regularly worked here in 1808, but only about 750,000 tons, all told, have been taken from them. For reasons which have been already given these mines cannot be profitably worked in competition with the anthracite mines of Pennsylvania, in which the location and formation of the coal beds are greatly superior. It is impossible to say when the coal of the great bituminous district of Pennsylvania and Ohio was first seen by white men. In the summer of 1755 General Braddock led his army through western Pennsylvania by a military road to that terrible defeat and slaughter in which he himself received his death wound. This road, laid out by the army’s engineers and graded by its men, was so well built that its course can still be traced, and it is seen to have crossed the outcrop of the Pittsburgh coal seam in many places. It is not improbable that a large number of the soldiers in the English army were familiar with the appearance of coal, and knew how to mine it and use it. Indeed, Colonel James Burd, who was engaged in the construction of the road, claims to have burned about a bushel of this coal on his camp-fire at that time. Some of the English soldiers who survived that terrible disaster to their arms afterward returned and purchased lands in the vicinity, and it is reasonable to suppose that the coal was dug and put to use by them. A lease, still in existence, dated April 11, 1767, making a grant of lands on “Coal Pitt Creek,” in Westmoreland County, indicates that there were coal openings there at that date. Captain Thomas Hutchins, who visited Fort Pitt (now Pittsburgh) in 1760, mentions the fact that he found an open coal mine on the opposite side of the Monongahela River, from which coal was being taken for the use of the garrison.