s a thermal spring, and its high temperature fully accounted for the
fertility of the hollow and the mildness of the air. But how were we to
get out of it? For look as I might, I could see no signs either of an
outlet or a current. Gondocori, who acted as pilot, quickly solved the
mystery. A buttress of rock, which in the distance looked like a part of
the mass, screened the entrance to a narrow waterway. Down this waterway
the cacique navigated the canoe. It ran in tortuous course between rocks
so high that at times we could see nothing save a strip of purple sky,
studded with stars. Here and there the channel widened out, and we caught
a glimpse of the sun; and at an immeasurable height above us towered the
_nevados_ (snowy slopes) of the Cordillera.

The stream, if that can be called a stream which does not move, had many
branches, and we could well believe, as Gondocori told us, that it was as
easy to lose one's self in this watery labyrinth as in a tropical forest.
In all Pachatupec there were not ten men besides himself who could pilot a
boat through its windings. He told us, also, that this was the only pass
between the eastern and western Cordillera in that part of the Andes, that
the journey from San Andrea to Pachatupec by any other route would be an
affair not of days but of weeks. The water was always warm and never
froze. Whence it came nobody could tell. Not from the melting of the snow,
for snow-water was cold, and this was always warm, winter and summer. For
his own part he thought its source was a spring, heated by volcanic fires,
and many others thought the same. Its depth was unknown; he himself had
tried to fathom it with the longest line he could find, yet had never
succeeded in touching ground.

Meanwhile we were making good progress, sometimes paddling, sometimes
poling (where the channel was narrow) and toward evening when, as I
reckoned, we had travelled about sixty miles, we shot suddenly into a
charming little lake with sylvan banks and a sandy beach.

Gondocori made fast the canoe to a tree, and we stepped ashore.

We are on the summit of a spur which stands out like a bastion from the
imposing mass of the Cordillera, through the very heart of which runs the
mysterious waterway we have just traversed. Two thousand feet or more
below is a broad plain, bounded on the west by a range of gaunt and
treeless hills ribbed with contorted rocks, which stretch north and south
farther than the eye can