Darkness was fast coming on and Frank concluded that the gang were going to their headquarters.
This was a gratifying reflection.
He was more than anxious to learn the location of this.
So intent did he become in following the villains that he forgot all else.
At length they entered a circuitous path among jagged masses of rock, and which led steadily upward.
For a mile this was continued.
Not until the peaks were about them and they were fairly among the clouds did the robbers come to a stop.
Then a deep chasm was reached, across which was one of those peculiar rope bridges seen nowhere else in the world.
This did not seem safe to cross.
Yet the sure-footed ponies, one by one, crossed the swaying bridge and passed safely to the other side.