It is necessary once more to define topographical bearings. Running north-east and south-west is this Cumberland Mountain, having an elevation of from twenty-five hundred to three thousand feet. Almost parallel with it, from ten to twenty miles away, and having an elevation of about two thousand feet, lies Pine Mountain, in Kentucky. In the outer or Cumberland Mountain it has now been seen that there are three remarkable gaps: Big Stone Gap on the east, where Powell's River cuts through Stone Mountain; Cumberland Gap intermediate, which is not a water-gap, but a depression in the mountain; and Big Creek Gap in the west, where Big Creek cuts through Walden's Mountain--the last being about forty miles distant from the second, about ninety from the first. Now observe that in Pine Mountain there are three water-gaps having a striking relation to the gaps in the Cumberland--that is, behind Cumberland Gap is the pass at Pineville; behind Big Stone Gap and beyond it at the end of the mountain are the Breaks of Sandy; and behind Big Creek Gap are the Narrows, a natural water-gap connecting Tennessee with Kentucky. But it has been seen that the English have had to tunnel Cumberland Mountain at Middlesborough in order to open the valley between Pine and Cumberland mountains to railroad connections with the south. It has also been seen that at Big Stone Gap it has been found necessary to plan for a vast tunnel under Big Black Mountain, and also under Pine Mountain, in order to establish north and south connections for railroads, and control the development of south-east Kentucky and south-west Virginia. But now mark the advantage of the situation at Big Creek Gap: a water-gap at railroad level giving entrance from the south, and seventeen miles distant a corresponding water-gap at railroad level giving exit from the south and entrance from the north. There is thus afforded a double natural gateway at this point, and at this point alone--an inestimable advantage. Here, then, is discovered a third distinct centre in Cumberland Mountain where the new industrial civilization of the South is expected to work. All the general conditions elsewhere stated are here found present--timbers, coals, and ores, limestone, granite, water, scenery, climate, flora; the beauty is the same, the wealth not less.