, but must make our first
exploration at once. Lord John had an electric torch in his knapsack,
and this had to serve us as light. He advanced, throwing his little
clear circlet of yellow radiance before him, while in single file we
followed at his heels.

The cave had evidently been water-worn, the sides being smooth and the
floor covered with rounded stones. It was of such a size that a single
man could just fit through by stooping. For fifty yards it ran almost
straight into the rock, and then it ascended at an angle of forty-five.
Presently this incline became even steeper, and we found ourselves
climbing upon hands and knees among loose rubble which slid from
beneath us. Suddenly an exclamation broke from Lord Roxton.

"It's blocked!" said he.

Clustering behind him we saw in the yellow field of light a wall of
broken basalt which extended to the ceiling.

"The roof has fallen in!"

In vain we dragged out some of the pieces. The only effect was that
the larger ones became detached and threatened to roll down the
gradient and crush us. It was evident that the obstacle was far beyond
any efforts which we could make to remove it. The road by which Maple
White had ascended was no longer available.

Too much cast down to speak, we stumbled down the dark tunnel and made
our way back to the camp.

One incident occurred, however, before we left the gorge, which is of
importance in view of what came afterwards.

We had gathered in a little group at the bottom of the chasm, some
forty feet beneath the mouth of the cave, when a huge rock rolled
suddenly downwards--and shot past us with tremendous force. It was the
narrowest escape for one or all of us. We could not ourselves see
whence the rock had come, but our half-breed servants, who were still
at the opening of the cave, said that it had flown past them, and must
therefore have fallen from the summit. Looking upwards, we could see
no sign of movement above us amidst the green jungle which topped the
cliff. There could be little doubt, however, that the stone was aimed
at us, so the incident surely pointed to humanity--and malevolent
humanity--upon the plateau.

We withdrew hurriedly from the chasm, our minds full of this new
development and its bearing upon our plans. The situation was
difficult enough before, but if the obstructions of Nature were
increased by the deliberate opposition of man, then our case was indeed
a hopeless one. And yet, as