The ground traversed that afternoon was not so free from bush as we had hitherto found, being in many places thickly covered with dense cerrado (abounding in immense quantities of the india-rubber-producing Mangaba-tree), where progress was very slow and difficult, and required the free use of our wood-knives. After a long and wearisome march, we reached the valley of the Sapao again, quite eight miles from the peccaries' haunt. I found the river valley presented much the same characteristics as we had found lower down. For the purposes of a railway it is admirable; the gradients are practically level, and the only works of art required would be in crossing the many _burity_ swamps that intersect the route, and these, although numerous, are narrow. Even the Rio Sapao itself could doubtless be made into a good canal, in the absence of a railway, for there is plenty of water, and the ground offers great facilities for straightening its course. Especial care was taken in preparing the camp that night. The Don and Jose superintended the operation of constructing the fort, the sides of which were further protected by spreading over them the hides used for covering the packs of the mules. Bush was also cut to make up and enlarge the defences, and a strong stake was driven into the ground inside the fort for the purpose of securing the dogs in case the peccaries arrived. The camp was made on the borders of a clump of trees, to which we were enabled to sling the hammocks, no one caring to sleep on terra firma that night, but two of the men who were unprovided with hammocks spread their hides on the ground inside the fort. After dinner, of course, peccaries formed the sole subject of conversation, but hour after hour went by, yet no signs of their presence appeared; and, after arranging the watches for the night, we turned in, and with the fatigues of the day I was soon asleep.