The minimum temperature was only 55° Fahr. during the night, but it was so damp that my men felt the cold intensely, especially as there were gusts of a sharp breeze from the north-east. Moreover, in the deep hollow with thick grass in which we camped (elev. 2,200 ft. above the sea level) we suffered absolute torture from the swarms of carrapatos of all sizes, mosquitoes, and flies. The air and earth were thick with them. The water was dirty and almost undrinkable, as it passed through a lot of decomposing vegetation.
I was glad when Filippe reappeared and we were able to leave that terrible spot. Great undulations were now met with, 300 ft. and more in height.
Only 1½ kil. farther on we came to the Presidente stream, flowing south (elev. 2,100 ft.) over a bed of ashes, while its banks were formed of thick deposits of finely powdered yellow volcanic sand and dust.
We went over a huge dome covered with a stratum of brown sand, exposing on its western side a large wall of igneous rock with much-fissured strata dipping to the north-west. Immense isolated rocks showed vertical strata, demonstrating plainly that they had been considerably disturbed at some epoch or other.
We were on the bank of another stream (elev. 1,950 ft.) flowing south—the Capim Branco. We were then in another great and deep basin extending from north-west to south-east, in the north-western part of which could be seen on the summit of the rounded hill-tops and spurs an overlapping of rock, evidently produced when in a molten condition. In the south-western part of the slope encircling this great valley there stood another great barrier, formed also by a flow of molten rock curling over itself, as it were, and above this stood angular and pointed shoots of molten stuff of a subsequent origin. Large slabs of the latter could be separated easily from the underlying flow.
From the summit of that rocky prominence was obtained a lovely panorama of a great plateau, a portion of which had been eroded into a wall (E.N.E.) with three buttresses: another portion was gradually assuming a similar shape. The plateau had a great spur projecting westward. A crater had formed with a broken-up side to the west, leaving the conical-shaped remains of its fragmentary mouth. The plateau ended after describing a sweeping curve—almost a semicircle.
In the centre of the immense basin before us were successions of high undulations—like great waves—extending southward in parallel lines (east to west). From the point of vantage on which I stood I could count as many as eight of those huge lines of waves. Evidently at some remote period—it would be difficult to say how many thousands of years ago—that was a gigantic mass of molten stuff in commotion. In many places it was apparent that the great waves of molten rock had flowed over and partly overlapped the lower ones. In its higher north-easterly point the basin was wooded.
The great basin extended southward. In that direction all the lower ridges with their arched backs showed a depression or dip. On the S.S.W. two more great domes of wonderfully perfect curves were to be observed, and on the south-west stood an isolated gigantic quadrangular mountain of solid rock, with the usual buttresses in the lower portion typical of that region.
To the south-east a lovely square-shaped plateau of marvellously graceful lines stood prominent in the centre of the basin. In the same direction, only a few hundred yards off, was a most peculiar angular rock, which looked exactly like the magnified crest of an immense wave. That was just what it had been formerly—the wave, of course, of a gigantic molten mass of rock, set in violent motion by an immeasurable force. It was the terminal point of the great succession of rocky waves which we had skirted to the north in order to arrive at that point, and which extended from the great semicircle we had passed the previous day.
