Strange Rock-Carvings of Matto Grosso.
At the terminal point of those rocky waves—or wherever the rock was exposed—it was evident that all those undulations had received a similar movement and had formed the great backbone range of rock, fully exposed in the last undulation. I had observed the continuation of this great rock crest the previous day in the basin previous to reaching the Capim Branco valley. There it crossed the spur on which I was—"Observation Spur," I shall call it for purposes of identification—almost at right angles. It seemed as if two forces had been acting simultaneously but in different directions, and at various points had come into conflict and eventually had overrun each other.
The last great rocky crest at Capim Branco, when seen in profile, looked like a huge monolith with a slight inclination to the south-east. The formation of the rock itself showed a frothy appearance, such as is common with any liquefied matter while in a state of ebullition.
It is quite possible, too, that the great wave of molten matter travelling from north-east to south-west, upon encountering some obstacle, had its run interrupted and had cooled down, while the upper portion of it, from the impetus received, curled over the summit of the arrested solidified rock below.
In fact, there was plenty of evidence to show that while the lower stratum cooled down other sheets of lava flowed above it, forming many successive layers. In the eastern part, where they were at an angle of 40°, these had cracked considerably in cooling. The central part of the great wave was entirely made up of vertically fissured strata. The lower half of the mass of rock showed markedly that it was an anterior wave to the upper.
There was a wide gap formed by the volcanic crack between this and the continuation of the undulations to the south-west, which got lower and lower. Perhaps before the crack occurred that hill was like the others on the east and west of it, padded with red earth. It must have become barren by the great shock which caused the surface of the earth to divide, and which no doubt shook the surface deposits down. In examining its north-eastern neighbour it could be seen that it actually tumbled over when the subsidence occurred, leaving a gap a few hundred metres wide.
A short distance beyond, on the S.S.E., was an interesting table-land sloping to the north-east, on the north side of which could be observed yet one more beautiful semicircular extinct crater. The rim, or lip of lava of this crater, had fissured in such a peculiar way as to give the appearance of a row of rectangular windows. The sections of the crater which remained standing showed two conical buttresses above massive cylindrical bases. From the crater started a huge, deep crack, 30 to 50 ft. deep and 20 to 100 ft. wide, which farther down became the actual bed of the stream. On both sides of this crack was a deep deposit of red earth and sand, the stratum below this being a solid mass of lava. The crater on the north-east side of the mountain had an inclination to the north, but was quite vertical on the south side.
Beautiful crystals were to be found in abundance on this mound, as well as great quantities of marble chips and crystallized rock in various forms.
On the side of this strange mound of rock I found some curious shallow caves, formed by great fissures in the rock. The vertical outer walls of these caves were painted white with lime dissolved in water. There were some puzzling carvings, which interested me greatly. I could not quite make up my mind at first whether those carvings had been made by Indians or whether they were the work of escaped negro slaves who had found shelter in those distant caves. In character they appeared to me Indian. Negroes, as a rule, are not much given to rock-carving in order to record thoughts or events. Moreover, those primitive carvings showed strong characteristics of hunting people, such as the Indians were. There were conventional attempts at designing human figures—both male and female—by mere lines such as a child would draw: one round dot for the head and one line each for the body, arms, and legs. Curiously enough—and this persuaded me that the drawings had been done by Indians—none of the figures possessed more than three fingers or toes to any extremity. As we have seen, the Indians cannot count beyond three—unlike members of most African tribes, who can all count at least up to five. This, nevertheless, did not apply to representations of footmarks, both human and animal—which were reproduced with admirable fidelity, I think because the actual footprints on the rock itself had been used as a guide before the carving had been made. I saw the representation of a human footmark, the left, with five toes, and the shape of the foot correctly drawn. Evidently the artist or a friend had stood on his right foot while applying the left to the side of the rock. When they attempted to draw a human foot on a scale smaller than nature, they limited themselves to carving two lines at a wide angle, to form the heel, and five dots to represent the toes.
