Titus Livius (Livy), The History of Rome, Book 30
Cyrus Evans, Ed.

8. Scipio, considering that Syphax and the Carthaginians could make no further efforts, gave his whole attention to the siege of Utica, and was now bringing up his engines to the walls, when he was diverted from his purpose by a report of the renewal of the war; [2] and, leaving small forces merely to keep up the appearence of a siege by sea and land, he set out himself with the main strength of his army to meet the enemy. [3] At first he took up his position on an eminence about five miles distant from the king's camp. The next day, coming down with his cavalry into a place called the great plains, which lay at the foot of that eminence, he spent the day in advancing up to the outposts of the enemy, and provoking them by skirmishing attacks. [4] During the ensuing two days, irregular excursions were made by both sides alternately, but nothing worthy of notice was achieved. On the fourth day, both sides came down in battle-array. [5] The Romans placed their principes behind the spearmen, which latter formed the front line, and the triarii they stationed in reserve; the Italian cavalry they opposed to the enemy in the right wing, the Numidians and Masinissa on the left. [6] Syphax and Hasdrubal, placing the Numidians against the Italian cavalry, and the Carthaginians opposite to Masinissa, received the Celtiberians into the centre of their line, to face the Roman legions. Thus arranged, they then commenced the encounter. [7] At the first charge, both the wings, the Numidians and Carthaginians, were together driven from their ground; for neither could the Numidians, who consisted principally of rustics, sustain [p. 1292]the shock of the Roman cavalry, nor the Carthaginians, who were also raw soldiers, withstand Masinissa, who, in addition to other circumstances, was rendered formidable by his recent victory. [8] The Celtiberian line, though stript of the support of both the wings, stood their ground; for neither did any hope of safety by flight present itself, as they were ignorant of the country, nor could they expect pardon from Scipio, against whom, though he had deserved well both of them and their nation, they had come into Africa to fight for hire. [9] Surrounded, therefore, on all sides by the enemy, they died with obstinate resolution, falling one upon another; and, while the attention of all was turned upon them, Syphax and Hasdrubal gained a considerable space of time to effect their escape. The victors, fatigued with the slaughter, which had continued for a greater length of time than the battle, were interrupted by the night.