If the veld can only be compared with the sea, the kopjes which accentuate, rather than relieve, its monotony resemble in as marked a degree the isolated islands which rise abruptly from the waters of some tropic archipelago. Sometimes, indeed, the kopjes form a rough series of broken knolls, extending over a space of several miles, as, for instance, the ridges of Magersfontein and Spytfontein, between Kimberley and the Modder; sometimes a group of three or four, disposed irregularly in all directions, become a conspicuous landmark, as at the positions of Belmont and Graspan; and it is not uncommon to find larger masses, not less irregular, enclosing the river reaches which their drainage has created, among which may be enumerated the heights south-east of Jacobsdal, and by the river Riet, and those about Koffyfontein and Jagersfontein on the same stream. [Sidenote: Better for view than defence.] But, as a rule, the kopje of the veld is a lonely hill, a mass of igneous rock--flat-topped or sharp-pointed. From 200 to 800 feet in height, without spur or underfeature, accessible only by winding paths among gigantic boulders, sheer of face and narrow of crest, it is more useful as a post of observation than as a natural fortress; for it can almost always be surrounded, and the line of retreat, as a general rule, is naked to view and fire. [Sidenote: Boer States as defensive terrain.] So far as tactical positions are concerned, any force on the defensive upon the veld of the Boer States must be mainly dependent on the rivers. Yet the spurs of the Drakensberg, blending in a range of ridges, form a mountain stronghold admirably adapted for guerilla warfare; and all along the Basuto border, at a distance of from 10 to 20 miles west of the Caledon, stands out a series of high, detached hills, which form a covered way along the eastern boundary of the Free State, crossing the Orange, and leading into the recesses of the Stormberg Mountains. [Sidenote: Natal features.] For every wavelet of land upon the surface of the Boer States, a hundred great billows stand up in Natal. Kopje succeeds kopje, all steep, and many precipitous, yet not the bare, stony cairns of the transmontane regions, but moist green masses of verdure, seldom parched even in the dry season, and in the wet, glistening with a thousand cascades; not severely conical or rectangular, like the bizarre eminences which cover Cape Colony with the models of a school of geometry, but nobly outlined. Many of the foothills, it is true, are mere heaps of rock and stone; but even these are rarely such naked and uncompromising piles as are found on the higher levels. Even where northern Natal occasionally widens and subsides to a savannah, as it does below the Biggarsberg, and again south of Colenso, the expanse, compared with the tremendous stretches of the Boer veld, is but a meadow. [Sidenote: Healthy theatre sole favour for invader.]