But more than this. The large window-like opening was bi-sected by the silvery-grey trunk of a lofty silk-cotton tree, and somewhat nearer to the river a tall oil palm held aloft its plumy head like a bunch of green ostrich feathers. I climbed the bank, and taking my stand upon a smooth knoll covered with thick moss, looked steadily through the opening at the hill; and now I perceived that the end of the red patch of cliff formed a nearly vertical line which appeared just half way between the stem of the palm and the trunk of the tree. This formed a leading mark which would enable me to find the spot again with certainty, and if the soil was not too rocky, this was an ideal place in which to bury the treasure. To test the hardness of the ground I stuck my knife into the moss, which it penetrated easily up to the hilt, showing that the soil underneath was soft and deep. Before returning, I had the curiosity to explore a little further this bank of the river, and, walking away from the water, I presently made a curious discovery; for I had not gone above twenty paces when I came to the water again. I at first thought I had merely reached a sharp bend in the river, but further examination showed that the land on which I stood was a small island, about a hundred yards long by twenty wide, and that it was separated from the mainland on either side by a stretch of water fully fifty yards in width. This was another piece of good fortune, for, being cut off on all sides by water, the place was peculiarly safe from accidental intrusion and, as I gathered up my knife and the shell-fish preparatory to returning, I felt that my mission had been highly successful. I had no difficulty in finding my way back. Starting from the knoll I marked the position of the oil palm and the tree, and waded across the river towards the former, going straight through the bushes until I reached it. Then I took a new direction to where I judged the tree to be, and soon its column-like trunk loomed above me out of the undergrowth. I sliced off two patches of bark to enable me to identify it for the present, and then taking a fresh bearing, I pushed on through the thick wood, watching my shadow attentively whenever the sunlight pierced the foliage. It was some time before I reached the track, and I began to fear that I had lost my way; but at length I crossed it, and in a few minutes more reached the foot of the hill. Evidently the track skirted the hill and diverged from the river. I found the patch of cliff with very little trouble, and when I thought I had reached the vicinity of the tunnel I gave a shrill whistle--the signal I had arranged with Bukári--which was immediately answered by a hail from above. Looking up I could see my comrade leaning out of the tunnel, and in a couple of minutes I had joined him.