nuts, which
when roasted tasted like the best of chestnuts and are nutritious; and
they caught a number of big piranhas, which were good eating. So we
all had a feast, and everybody had enough to eat and was happy.

By these rapids, at the fall, Cherrie found some strange carvings on a
bare mass of rock. They were evidently made by men a long time ago. As
far as is known, the Indians thereabouts make no such figures now.
They were in two groups, one on the surface of the rock facing the
land, the other on that facing the water. The latter were nearly
obliterated. The former were in good preservation, the figures sharply
cut into the rock. They consisted, upon the upper flat part of the
rock, of four multiple circles with a dot in the middle (O), very
accurately made and about a foot and a half in diameter; and below
them, on the side of the rock, four multiple m's or inverted w's (M).
What these curious symbols represented, or who made them, we could
not, of course, form the slightest idea. It may be that in a very
remote past some Indian tribes of comparatively advanced culture had
penetrated to this lovely river, just as we had now come to it. Before
white men came to South America there had already existed therein
various semi-civilizations, some rude, others fairly advanced, which
rose, flourished, and persisted through immemorial ages, and then
vanished. The vicissitudes in the history of humanity during its stay
on this southern continent have been as strange, varied, and
inexplicable as paleontology shows to have been the case, on the same
continent, in the history of the higher forms of animal life during
the age of mammals. Colonel Rondon stated that such figures as these
are not found anywhere else in Matto Grosso where he has been, and
therefore it was all the more strange to find them in this one place
on the unknown river, never before visited by white men, which we were
descending.

Next morning we went about three kilometers before coming to some
steep hills, beautiful to look upon, clad as they were in dense, tall,
tropical forest, but ominous of new rapids. Sure enough, at their foot
we had to haul up and prepare for a long portage. The canoes we ran
down empty. Even so, we were within an ace of losing two, the lashed
couple in which I ordinarily journeyed. In a sharp bend of the rapids,
between two big curls, they were swept among the boulders and under
the matted branches which stretched out from th