As he descended thus slowly, the ladder seemed interminable and
the pit bottomless, yet he realized when at last he reached the
bottom that he could not have descended more than fifty feet.
The bottom of the ladder rested on a narrow ledge paved with what
felt like large round stones, but what he knew from experience to
be human skulls. He could not but marvel as to where so many
countless thousands of the things had come from, until he paused
to consider that the infancy of Caspak dated doubtlessly back
into remote ages, far beyond what the outer world considered the
beginning of earthly time. For all these eons the Wieroos might
have been collecting human skulls from their enemies and their
own dead--enough to have built an entire city of them.

Feeling his way along the narrow ledge, Bradley came presently to
a blank wall that stretched out over the water swirling beneath
him, as far as he could reach. Stooping, he groped about with
one hand, reaching down toward the surface of the water, and
discovered that the bottom of the wall arched above the stream.
How much space there was between the water and the arch he could
not tell, nor how deep the former. There was only one way in
which he might learn these things, and that was to lower himself
into the stream. For only an instant he hesitated weighing
his chances. Behind him lay almost certainly the horrid fate of
An-Tak; before him nothing worse than a comparatively painless
death by drowning. Holding his haversack above his head with one
hand he lowered his feet slowly over the edge of the narrow platform.
Almost immediately he felt the swirling of cold water about his
ankles, and then with a silent prayer he let himself drop gently
into the stream.