The latter had worn out a deep hollow and he scrambled over the rocks in order to look down into its revolving depths.

There was nothing there, and when going back he made his way across some worn slabs that had been covered until the water sank to an unusually low level.

By and by he stopped at the edge of a pool.

A small round object that was not the color of the stones lay at the bottom.
Thirlwell knelt down and rolling up his sleeve got the object out.

It was made of white metal that had tarnished but not corroded, and looked like an old-fashioned pocket tobacco-box.