MARCHING BY COMPASS 
Central Brazil was certainly a country of flat sky-lines 
—- so flat that often when the distance became of a pure 
cobalt blue, one had the impression of overlooking an 
immense ocean, to which the green undulations in sweep¬ 
ing lines in the nearer foreground added the impression 
of great waves. 
It was indeed difficult to realize the stupendous 
magnitude of the scenes we constantly had before us. 
That day, for instance, the plateau to the north of us 
stretched across towards the east for 70° of the compass 
from bearings magnetic 320° (north-northwest) to 30° 
(north-northeast). Above the plateau was a strange 
effect of clouds — a succession of arrow-shaped, nebulous 
masses. 
We still came upon basins of grey ashes — cuvettes 
— but in that region these were deeper than those we had 
observed so far, had luxuriant grass, and in the moist 
centre the invariable line of burity palm and heavily 
foliaged trees. 
Travelling on a northerly course, and then to the north¬ 
west, we descended, after having marched twenty kilo¬ 
metres, into a basin (elevation 1,950 feet) where a thick 
and wide deposit of fine white sand and minute crystals' 
covered the deeper part of the depression. Then, farther 
on, the sand was replaced by the usual deposits of grey 
ashes which filled the remainder of the basin. A stream¬ 
let, which had its birth in the centre of the basin, flowed 
north into the Rio Manso, along one of the many cracks 
which were to be seen in that region and in the depressions 
we had previously crossed. We came upon a mighty 
flow of red and black lava with a somewhat frothy surface. 
It was in superposed layers from one to six inches deep, 
with an inclination to the east of 15°. The flow itself 
had a direction from west to east. 
As we were marching by compass, with no trail what¬ 
ever, we found ourselves entangled in a swampy valley 
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