The cliff-dwellers had chipped and chipped away at this boulder till it rested its tremendous bulk upon a mere pin-point of its surface.

Venters pondered.

Why had the little stone-men hacked away at that big boulder?
It bore no semblance to a statue or an idol or a godhead or a sphinx.

Instinctively he put his hands on it and pushed; then his shoulder and heaved.

The stone seemed to groan, to stir, to grate, and then to move.