I climbed up on the Paredãozinho volcano (2,100 ft. above the sea level) to examine its extinct crater, subdivided into two distinct large craters and a subsidiary one.
One of these craters extended from east to west, and had in one section on its rim a giant dome split into quadrangular and lozenge-shaped sections, not unlike magnified mosaic work. Next to it was a great hill with a vertical natural wall overlooking the crater itself. The horizontal strata of this natural wall, each about a foot thick, looked exactly like a wonderful masonry work, so perfectly straight were the strata, and the square and rectangular rocks laid in lines with such extraordinary regularity. This wall stood upon solid masses of rock of immense size—hundreds of feet in height.
The lip of the crater on the south side was just like the well-laid pavement of a city, so regularly had the lava cracked in contracting, thus leaving four- and five-sided geometrical figures, all well fitting in with their neighbours. Again, in this case, the lava, flowing over a convex surface, had contracted on the surface and caused the wonderful network of grooves. In one section the crater had the appearance of an ancient Roman or Etruscan amphitheatre with seats in many tiers or steps, separated by vertical cracks—as if cut out into separate blocks of stone.
Strange Formation of Volcanic Rock.
Volcanic Cavities (Matto Grosso).
On the east side of the greatest portion of one crater—which would seem to have been the most active of all—I found again immense boulders with stratified rock above them resembling masonry work, just the same as and at the same elevation as the layers I had examined in the larger elongated horseshoe crater. In the centre of the smaller crater there flowed a rivulet of crystal-like water most delicious to drink. Undoubtedly those eastern rocks were the lip of the crater, for I discovered there two flows of lava in corrugations and network designs such as we had observed on the summit of the greater section. I had great difficulty in climbing up the steep internal walls of the crater, and on the steep slopes with dried grass, which was slippery to a degree. On the top of the crater were great masses of carbonated rock; also patches of lapilli, and red and white sand, plentiful everywhere in that zone.
