Their then encampment was situate on the edge of the forest belt. Beyond the latter the country stretched away in vast, well-nigh treeless plains. Now a peculiar feature of these plains was the frequent recurrence of abrupt granite _kopjes_, at first glance not unlike moorland tors. But more than one of them, when arrived at, wore the aspect of a complete Druidical ring--a circle of stones crowning the rise, with a slight depression of ground within the centre. One of these Hazon, who had been over the ground before, resolved should serve them as a natural fortress, whence to resist the fierce and formidable foe now advancing against them. With surprising readiness the march began. Loads were shouldered and slaves yoked together extra firmly. Those who were too weak to keep up the pace--treble that of the normal one--at which they were hurried forward, were ruthlessly speared; but whether they were slain by their captors or by the pitiless Ba-gcatya mattered but little. The _kopje_ which Hazon had selected was situated about four miles from the forest belt. No better natural fortress could have been chosen; for it consisted of a complete circle of low rocks, of about two hundred yards' diameter, and commanded an open sweep of at least a mile on every side. Laurence and Holmes were loud in their admiration and interest. "These are old craters, I reckon," said Hazon; "not volcanic, but mud-springs. This plain, you notice, is considerably below the level of the forest country. Depend upon it, the thing was once a big swamp, with great boiling, bubbling mud-holes." No time was it, however, for speculations of a scientific nature; and accordingly the leaders proceeded to dispose their lines of defence. This was soon done, for the three white men and Lutali had arranged all that during the march. The Wangoni were of no great use, save in pursuit of a defeated enemy. They could hardly have hit a haystack once in six shots, nor did Hazon care to intrust with firearms such a turbulent and unruly crew. But the slavers were all fair marksmen--some indeed, among them Lutali, being not far short of dead shots. These were disposed around the circle of rocks so as to form a ring of fire; and the rocks themselves were heightened wherever necessary with some of the loads, or with such piles of loose stones as could be collected in time. The part allotted to the Wangoni was that of a reserve force, in the event of the enemy carrying any given point, and thus necessitating hand-to-hand conflict. The slaves, firmly secured, were placed in the center of the great circle.