along the Rio das Porcas,
flowing westward. There, north of the stream, we went across more clean
campos, 1,700 metres wide, bounded to the north by the thickly-wooded
hill-range Keboh, extending before us from east to west.

We crossed this range in the centre, during a strong gale from the
south-west. The wind cleared the sky, that had been overcast and had made
the atmosphere heavy. Again that afternoon, when the wind ceased, I
noticed the peculiar striations in the sky--not in straight lines that
time, but in great and most regular curves converging to the west.

The valley got narrower as we went along. Two twin conical hills ended
the northern extremity of the range (south-east to north-west) which we
had on our left--a great mass of granite blocks in the centre of the
plain rising higher and higher into regular domes. The plain itself, on
an incline, showed two swellings of great magnitude, the one to our right
about 120 ft. higher than the plain, the elevation of which was 1,000 ft.
On the west side of those two swellings was a confused mass of huge
blocks of granite--of all sizes and shapes--which to all appearances had
been shot up from underneath by some internal force. They were outwardly
much blackened by the action of fire, but internally were of a grey tint.
A little farther we were encircled by basaltic columns of great height,
many of them fractured, forming a fantastic sky-line. Some resembled the
spires of a cathedral; groups of others had the appearance of the ruins
of an ancient fortress; others stood up like giant obelisks; while
accumulations of others formed more or less regular pyramids.

After leaving that strange basin, we were once more travelling across
patches of clean _chapada_ and dirty _chapada_--according to the soil and
quantity of moisture; then over arid campos spreading for 15 kil. without
one single drop of water.

At sundown, after having gone over several undulations varying from 850
to 900 ft. above the sea level, we went over a hill slightly higher--950
ft.--with a summit of ashes, red earth, and yellow lava pellets, as well
as great sheets of foliated lava.

Under a most wonderful effect of light to the west--three superposed
horizontal bands of luminous yellow, violet and brilliant vermilion, over
the deep cobalt mountain range in the distance--we arrived, my men being
thirsty and tired, at a little rivulet. We had marched 42 kil. that day.

My men felt the cold intense