Advancing in single file along the bank of the stream, we soon found that it narrowed down to a mere brook, and finally that it lost itself in a great green morass of sponge-like mosses, into which we sank up to our knees. The place was horribly haunted by clouds of mosquitoes and every form of flying pest, so we were glad to find solid ground again and to make a circuit among the trees, which enabled us to outflank this pestilent morass, which droned like an organ in the distance, so loud was it with insect life.
On the second day after leaving our canoes we found that the whole character of the country changed. Our road was persistently upwards, and as we ascended the woods became thinner and lost their tropical luxuriance. The huge trees of the alluvial Amazonian plain gave place to the Phoenix and coco palms, growing in scattered clumps, with thick brushwood between. In the damper hollows the Mauritia palms threw out their graceful drooping fronds. We traveled entirely by compass, and once or twice there were differences of opinion between Challenger and the two Indians, when, to quote the Professor's indignant words, the whole party agreed to "trust the fallacious instincts of undeveloped savages rather than the highest product of modern European culture." That we were justified in doing so was shown upon the third day, when Challenger admitted that he recognized several landmarks of his former journey, and in one spot we actually came upon four fire-blackened stones, which must have marked a camping-place.
The road still ascended, and we crossed a rock-studded slope which took two days to traverse. The vegetation had again changed, and only the vegetable ivory tree remained, with a great profusion of wonderful orchids, among which I learned to recognize the rare Nuttonia Vexillaria and the glorious pink and scarlet blossoms of Cattleya and odontoglossum. Occasional brooks with pebbly bottoms and fern-draped banks gurgled down the shallow gorges in the hill, and offered good camping-grounds every evening on the banks of some rock-studded pool, where swarms of little blue-backed fish, about the size and shape of English trout, gave us a delicious supper.
On the ninth day after leaving the canoes, having done, as I reckon, about a hundred and twenty miles, we began to emerge from the trees, which had grown smaller until they were mere shrubs. Their place was taken by an immense wilderness of bamboo, which grew so thickly that we could only penetrate it by cutting a pathway with the machetes and billhooks of the Indians. It took us a long day, traveling from seven in the morning till eight at night, with only two breaks of one hour each, to get through this obstacle. Anything more monotonous and wearying could not be imagined, for, even at the most open places, I could not see more than ten or twelve yards, while usually my vision was limited to the back of Lord John's cotton jacket in front of me, and to the yellow wall within a foot of me on either side. From above came one thin knife-edge of sunshine, and fifteen feet over our heads one saw the tops of the reeds swaying against the deep blue sky. I do not know what kind of creatures inhabit such a thicket, but several times we heard the plunging of large, heavy animals quite close to us. From their sounds Lord John judged them to be some form of wild cattle. Just as night fell we cleared the belt of bamboos, and at once formed our camp, exhausted by the interminable day.
Early next morning we were again afoot, and found that the character of the country had changed once again. Behind us was the wall of bamboo, as definite as if it marked the course of a river. In front was an open plain, sloping slightly upwards and dotted with clumps of tree-ferns, the whole curving before us until it ended in a long, whale-backed ridge. This we reached about midday, only to find a shallow valley beyond, rising once again into a gentle incline which led to a low, rounded sky-line. It was here, while we crossed the first of these hills, that an incident occurred which may or may not have been important.