II. The UPLANDS of the British Isles consist of undulating plains or plateaux which lie from 1000 to more than 2000 feet above the sea. Seen from a distance, they look like ranges of hill or mountain, but without that variety of peak and crest which a true mountain outline would present. Though they may rise steeply out of the lower grounds, we have only to climb to their summit to find ourselves at the edge of a wide rolling platform, which may stretch for leagues without ever rising into any sharp prominence, or departing from the same monotony of moorland. Yet if we attempt to cross this seemingly continuous tableland, we find our progress barred by many valleys which, deep sunk beneath the general level, divide the plateau into separate blocks or ridges. The surface of these uplands is for the most part treeless and even bushless. Where not covered with peat-moss, it is clothed with bent or with heather, kept short and green by periodical burning in the springtime. Herds of cattle and flocks of sheep wander over the pastures, but, save the stone fences, there is little other visible trace of human occupation. It is in the little hollows that lead down into the main valleys, and in these valleys themselves, that trees make their appearance, first in scattered saplings of birch, alder or mountain-ash, and then in thicker copsewoods or in artificial plantations of fir and larch. In these sheltered depressions, the farms and villages of the region have been planted, and cultivation has been slowly pushed upward on the slopes of the fells. Thus the larger part of the area of the uplands is uninhabited, the population being restricted to the more or less sheltered 'hopes,' hollows, dales, and valleys. This type of scenery presents many local varieties, according to the geological structure of the ground. Where the rocks have been but little disturbed, the sides of the valleys display a succession of parallel bars of stone with intervening grassy slopes, such as may be seen among the moors of the East Riding, or in the dales of the Pennine Chain. Where, on the other hand, the rocks have been much compressed and pushed over each other by powerful movements of the terrestrial crust, their erosion has given rise to no regular topography, but they decay into rounded forms covered with heath and herbage, or breaking here and there into rocky scarps, as in Wales and southern Scotland.