The smaller crater—it seemed to me—must have been a mere safety valve for the larger one. Its elevation, it will be noticed, was the same as that of the latter. From the summit of the one on which I was standing I could perceive the other to the E.N.E., forming the eastern boundary of this immense volcanic hollow. The southern part of this great double crater was subdivided into several sections, all in great rocky terraces—quite vertical except in their lower portion, which was sloping and had evidently been filled to a great extent by an accumulation of ashes and erupted refuse. On the side on which I stood, however, the crater had not the diabolical, quite awe-inspiring, appearance of the larger section of the huge volcanic mouth—quite unscaleable by humans in its central section. In the deep cracks in the rock were several small grottoes. I experienced some difficulty and much fatigue in climbing to the top (elev. 1,750 ft.) of the extinct volcano, and especially in reaching the lip of the crater, owing to the thick and much entangled scrub with innumerable thorns.
Our camp was at 1,500 ft., in a delightful spot at the junction of two streams, one from the south descending from the volcano, the other from the north. The two rivers united flowed north—I think eventually into the Rio das Mortes.
When we moved out of camp on May 25th (temperature, minimum 62°, maximum 80° Fahr.) I noticed that, after passing the wall-like section of the crater in the northern aspect, there were strata with a dip south in the inner part of the crater. The northern face of this vertical wall showed thick strata cracked into squares and rectangles with a dip in two different directions at an angle. There a draining channel had formed. Two rows of circular holes—like port-holes—were to be seen, one directly under the summit, the other one-third down the cliff side. A giant rectangular tower of solid rock stood erect parallel to the great wall. Skirting this vertical wall we travelled north-west-by-west, rising gradually to 1,800 ft. on a deep layer of red volcanic sand and grey ashes.
Looking back to the east we had a complete view of the two-tiered plateaux with their vertical northern walls, showing a dip south in their stratification. A crowning mound could also be observed surpassing their height, when we rose still higher to 1,900 ft. on the summit of a ledge of cracked lava with a slant west-wards. On the eastern side, where it had crumbled owing to a subsidence, it showed a rounded moulding, whereas on the other side were great waves of lava. The lava had flowed from east to west.
After leaving this curious spot we went over undulating red and ochre-coloured sand and more grey ashes. We rose twice to an elevation of 2,000 ft. We crossed a streamlet of delicious water flowing north over a red lava bed. Then more and more ashes were found all along. A second stream—also flowing north—was then negotiated, also over a red lava bed (elev. 1,800 ft.), after which we climbed to 2,000 ft., descending soon after to 1,900 ft. on the banks of another river flowing north-east.
At this spot were two more enormous lava-flows—one on each side of the stream, and extending in a tortuous course from south-west to north-east. The lava had flowed north-east.
On rising slowly in deep red sand to an elevation of 2,100 ft. we saw two prominent elevations of brilliant red colouring to the south—they, too, with vertical cliffs to the north. To the west loomed two huge twin plateaux separated by an immense crack, also with vertical walls to the north and a slight dip south in the strata forming the various terraces.
