The Salesians told me that while digging to make the foundations for one of their buildings they had found—only 3 ft. under ground—in the sandy soil several earthen pots of great antiquity, in excellent preservation, as well as a fireplace with ashes and charcoal. The sand had evidently accumulated in the valley below there owing to wind and not to water. The frail pottery, imperfectly baked, would have crumbled away quickly in moisture.
On May 20th (min. 58° Fahr., max. 85°) we were again off toward the west, travelling over great domes of red lava, the higher portions of which were covered by layers of ashes and red sand. We were at an elevation of 1,480 ft. in the deep basin of the Rio Barreiros and Rio das Garças, but we soon went over three consecutive ridges, 1,550 ft. above the sea level, with delicious campos and a bosquet of trees here and there. In the arc of a circle extending from north-west to south-west we had in front of us a beautiful view. Previous to reaching the third ridge, that day, we also had behind us a wonderful panorama of the great plateau described in a previous chapter.
On travelling over a fourth elevation we found ourselves upon another immense dome of red volcanic rock, blackened on the surface, as if by fire, and with the peculiar striations we had noticed once or twice before. In this case there were cross striations as well, the direction of one set of parallel marks being from north-west to south-east, of the other set north-east to south-west, thus forming lozenges, each about 60 cm. across. All those lozenges were so regularly cut that the ensemble gave the appearance of a well-made pavement. Then I noticed some peculiar great cavities in the rock, like those formed by glacial action. In fact, on a superficial examination, it seemed almost as if that region had first gone through a period of great revolution while in a state of semi-liquefaction owing to intense heat from fire, after which a sudden and intense cooling had taken place and covered the country perhaps even with ice. Whether the immense deposits of ashes and sand had been formed before or after the glacial period—if any such period ever existed in that particular region—could be merely a matter of speculation. In many places the sand, ashes, and red earth had almost consolidated into easily friable rock.
Where the actual rock was not exposed we had campos, campos, campos, stretching as far as the eye could see. Far from being monotonous, one had—or at least I had—a delightful sensation in riding across those interminable prairies of beautiful green. One could breathe the pure air with fully expanded lungs, and in that silent, reposeful solitude one felt almost as if the whole world belonged to one. We were not much worried by insects on those great open places; it was only on getting near patches of vegetation and near streams that we suffered from the attacks of those pests.
We saw few trees—all stunted and weak—as the padding of earth over the rocky under-strata did not permit their roots to go deep down, and therefore they grew up with difficulty and anæmic.
Twelve kilometres from the Rio Barreiros we came to a stream (elev. 1,400 ft.). On our left, rising above the inclined campos, was a triple undulation much higher than its neighbours. To the west stood two twin, well-rounded mounds, that my men named at once "the woman's breasts," which they much resembled.
We were still marching on deep deposits of ashes, and, higher, upon semi-hardened sandstone. On the northern side the twin hills had a different shape. They ended in a sharply pointed spur.
After going over an ochre-coloured sandy region (elev. 1,530 ft. above the sea level) we were again on magnificent undulating campos, dotted here and there with dark green shrubs and bosquets to the north, north-west, and north-east.
Beyond, to the north-east, loomed again in the far distance our mysterious plateau, of a pure cobalt blue where in shadow. As one ran one's eye along its sky-line it was almost flat for more than half its length, then came a slight dip, followed by a terraced dome. Then again a straight line followed by a slightly higher and more undulating sky-line with three steps in it, and a conical end at its eastern terminus. The most easterly point of all—the highest—resembled a castle with vertical sides. But of this we have already spoken, at the terminal point of the great divided range we had passed some days previously. The vertical cliffs of the plateau, where lighted by the sun, were of a brilliant red colour.
