The ground fell almost sheer six hundred feet to the flat bottom of the valley. Beneath, the Tugela curled along like a brown and very sinuous serpent. Never have I seen such violent twists and bends in a river. At times the waters seemed to loop back on themselves. One great loop bent towards us, and at the arch of this the little ferry of Potgieter's floated, moored to ropes which looked through the field glasses like a spider's web. The ford, approached by roads cut down through the steep bank, was beside it, but closed for the time being by the flood. The loop of river enclosed a great tongue of land which jutted from the hills on the enemy's side almost to our feet. A thousand yards from the tip of this tongue rose a line of low kopjes crowned with reddish stones. The whole tongue was virtually ours. Our guns on the heights or on the bank could sweep it from flank to flank, enfilade and cross fire. Therefore the passage of the river was assured. We had obtained what amounted to a practical bridgehead, and could cross whenever we thought fit. But the explanation of many things lay beyond. At the base of the tongue, where it sprang from the Boer side of the valley, the ground rose in a series of gentle grassy slopes to a long horseshoe of hills, and along this, both flanks resting securely on unfordable reaches of the river, out of range from our heights of any but the heaviest guns, approachable by a smooth grass glacis, which was exposed to two or three tiers of cross-fire and converging fire, ran the enemy's position. Please look at the sketch on p. 261, which shows nothing but what it is meant to. [Illustration: Plan of Potgieter's Ferry.] It will be seen that there is no difficulty in shelling the Boers out of the little kopjes, of fortifying them, and of passing the army on to the tip of the tongue; but to get off the tongue on to the smooth plateau that runs to Ladysmith it was necessary to force the tremendous Boer position enclosing the tongue. In technical language the possession of the heights virtually gave us a bridgehead on the Tugela, but the debouches from that bridgehead were barred by an exterior line of hills fortified and occupied by the enemy.