What astonished me greatly was that the line of demarcation between an utter desert and, say, a fine forest was almost as sharply marked as if it had been drawn with a rule.

A stretch of delightfully wooded country would follow the dreary wastes, and this in turn would give place to fairly high mountain ranges.
Once, during a temporary stay among one of the tribes, the chief showed me some very interesting caves among the low limestone ranges that were close by.

It was altogether a very rugged country.

Always on the look- out for something to interest and amuse me, and always filled with a strange, vague feeling that something _might_ turn up unexpectedly which would enable me to return to civilisation, I at once determined to explore these caves; and here I had a very strange and thrilling adventure.
Whilst roaming among the caves I came across a pit measuring perhaps twenty feet in diameter and eight feet or nine feet in depth.

It had a sandy bottom; and as I saw a curious-looking depression in one corner, I jumped down to investigate it, leaving Bruno barking at the edge of the pit, because I knew I should have some trouble in hoisting him up again if I allowed him to accompany me.