He had read of a class of people in Africa who never showed themselves above ground in daylight.
All of their work was done at night, and during the daytime they burrowed caverns in the ground and slept.
These people of the marble pueblo might be much the same. Frank began to believe that this was the way of it.
The light which he had seen the night before was no doubt used by the workmen in laying the stone and mortar for the structure.
But where did they find hiding places during the day?
Were there chambers or caverns underneath the marble pueblo?
Certainly the pigmy could not have disappeared so easily if there was not some method of hiding in some such manner.
Frank vaulted the parapet and began to examine the stone walls.
After some moments’ search to his surprise, as he touched one of the stones, it swung inward.
A long, narrow passage dark as Erebus was disclosed.