Page:Transactions of the Natural History Society of Northumberland, Durham, and Newcastle-upon-Tyne (1867).djvu/41

Rh White Lee. The whole occupies an area of about 200 square miles in Northumberland, and of 100 in Roxburghshire. This range is marked by distinctive physical features. The lowest level at which the porphyry appears is 200 feet above the sea, in Akeld Burn; but, rising steeply from the stratified rocks, it soon attains a high elevation, generally of not less than 1000 feet: Humbleton Hill, near Wooler, the scene of a famous border battle, is 977 feet high; Yeavering, of archaeological and historical celebrity, is 1182 feet; the Newton Tor is 1762 feet; Dunmore is 1860 feet; Windygyle, near the borders, is 1983 feet; rounded Hedgehope is 2348 feet; and broad-backed Cheviot, the highest, is 2676 feet above the sea level. Many of these high hills are of fine conical forms and roll into each other, being separated by short upland valleys or hopes; in others the division is made by narrow rugged and craggy clefts. Through deep valleys or gorges the burns and rivulets brawl over rocky channels, leaping over crags into highly picturesque linns, such as the Harthope and Linnhope Spouts. Naked though the mountains are, being treeless, nevertheless "sublimity breathes from their forms." Where the declivity is considerable long trains of angular rocks, detached from the mass, extend from near the summit to the base; and these, when weathered, have a purple hue, which blends well with the bright green herbage which here and there appears. Locally, these trains are called glitters or glidders, probably from gleiden (Anglo-Saxon), to slide.

Though the rock is hard, yet the felspar is liable to decomposition by the ordinary action of the elements, and the soil resulting is highly productive. The top of the higher hills is covered with peat and yields a coarse grass; but on their slopes, and on hills of less elevation, a fine grass grows well adapted for sheep pasturage. Though in the valleys, and ravines, and sheltered nooks several plants of rarity and interest flourish, yet this range, considering its extent, elevation, and composition, has not a rich Flora. Some plants, peculiar to igneous rocks, will be noticed when treating of the basalt; but others, which are confined to the Cheviots, have their habitat there more from elevation than from the mineral character of the rock; as for example, the