At a distance of about half a mile, or perhaps a little less, from the mouth of the river, the shore on our starboard hand merged into a low wooded point, round which we swept, out of the main channel, into a charming basin, some two miles wide, surrounded on every side by high land, sloping gently backward from the water's edge, and magnificently broken by deep, precipitous ravines, some of which could be traced from the heart of the surrounding hills clear down to the water's edge. The centre of the basin was occupied by an islet, roughly circular in shape, and about half a mile in diameter, as we discovered by pulling round it. This islet was the hiding-place of the treasure, if the cryptogram was to be believed; and I accordingly inspected it as narrowly as the swiftly gathering darkness would permit, so that I might carry a tolerably distinct impression of it in my mind's eye, as an aid to the plan that I must now definitely form and arrange before the next sunrise. As may be supposed, I had by this time got the words of the cryptogram off by heart--and, indeed, had destroyed the translation, lest it should fall into other hands--I therefore knew exactly what I had to look for as a mark to guide me to the hiding-place of the treasure, and accordingly kept a very sharp lookout for "the obelisk rock." There was only one rock to be seen on the islet that at all answered to this description, and that, so far as I could distinguish in the gloom, was a pointed, needle-like mass, forming the summit of a steep cliff that rose precipitously from the water's edge and constituted the northern extremity of the islet. But on getting round to the other side I was vexed and chagrined to find that the whole surface of the islet on the southern side of this curious cliff was densely overgrown with trees and scrub, which would certainly have to be cut deeply into in order to arrive at the spot where the treasure was said to be buried. This condition of affairs, natural enough though it was, had somehow never occurred to me; I had fully expected to find the hiding-place located in an open space that might be conveniently traversed in any and every direction, enabling the situation of the treasure to be determined by the simple process of measuring off a thousand feet in a direction due south from the base of the obelisk rock. Possibly that might have been the condition of the islet at the period when the treasure was buried--indeed, it very probably was--but there had been ample time for the ground to have become overgrown since then; and now it was so densely covered with vegetation that it would be hopeless to think of getting at the hiding-place without the assistance of the men. And that meant the absolute overthrow of my plan to keep the recovery of the treasure a secret from them!