The scenery was getting stranger and stranger every day. We began to notice solitary domes and cones in the landscape. That day, in fact, beyond the great campos we had before us a curious little well-rounded dome, standing up by itself upon an absolutely flat surface, at a considerable distance from the flat tableland which stood on one side, and of which formerly it evidently made part. Higher mountains, somewhat nearer to us, were on the south-west.
We had reached the River Corgo Fundo (elev. 1,250 ft.), along the banks of which the laminæ of red-baked rock could be observed with thin white layers between. Above was a lovely green pasture with a tuft of deep green trees, which looked exactly like a bit of a well-kept English park. We mounted up again to 1,430 ft., then went down another descent into a large plain with campos, upon which grew merely a few stunted trees. We were still travelling over deep deposits of sand.
The range to the north of us extended, to be accurate, from north-east to south-west, and at its south-westerly end possessed a dome not dissimilar to the one already described on our previous day's march. This one was perhaps more rounded and not quite so tall. It rose above the plateau in two well-defined terraces, especially on the north-east side, but was slightly worn and smoothed to the south-west. On the terminal mound—clearly separated from the range by erosion—seven distinct terraces could be counted, with some less defined intermediate ones.
In the bed of another stream flowing south—it was impossible to ascertain the names of these streamlets, for there was no one to tell, and none were marked on existing maps—another great flow of red lava was visible. This stream flowed into the Rio das Garças or Barreiros, only 500 metres away—an important watercourse, throwing itself eastward into the Rio das Mortes, one of the great tributaries of the upper Araguaya River.
CHAPTER XIII
The River Barreiros—A Country of Tablelands
The Rio Barreiros was about 100 metres wide. It was reached through a thick belt, 100 metres in width, of trees and bamboos of large diameter, which lined both its banks. The river flowed swiftly where we crossed it, over a bed of lava and baked rock, red and black, with huge treacherous pits and holes which rendered the job of crossing the stream dangerous for our animals. There were rapids lower down in the terraced mass of rock forming the river bottom. The rock, worn smooth by the water, was extremely slippery. It was only after we had all undressed and taken the baggage safely across on our heads—the river being too deep for the loads to remain on the saddles—that we successfully drove the animals over to the opposite bank.
On the banks I collected some specimens of the laminated red rock, which had no great crushing resistance when dry. It could be easily powdered under comparatively light pressure, and scratched with no difficulty with one's nails. It was of various densities of red tones, according to the amount of baking it had undergone. The superposed red strata had a dip northward in some localities. The rock was much fissured, and had either gone through excessive contraction in cooling or else perhaps had been shattered by some earthly commotion—such as must have occurred often in that region in ages gone by, for, if not, how could one account for finding scattered blocks of this red rock resting upon the surface of great stretches—sometimes for 20 or 30 kil.—of uninterrupted sand or ashes which covered such great expanses of that country?
