He called to the boy to hang on and to the others at the top to draw the line, and both were soon on the landing at the bottom of the shaft.
"I wonder where that hole goes ?" Jimmie asked, examining his fingers, the ends of which were torn from slipping on the rock.
"You came near finding out," Nestor replied.

"Regular rabbits, these old-timers were, to dig tunnels!" he added.
Then assisting Jimmie out of the shaft, Nestor asked the boys to get all the rope they had in their outfits, making a line as long as possible, and ease him down the steep incline.

In five minutes all was ready and, with a line 400 feet long attached to his waist, Nestor started down the tunnel.
As he passed along, half sliding, with the rope holding him back, the flashlight in hand, he saw that the passage had been cut along the line of a natural fault in the volcanic rock.

It was clear that, during some seismic disturbance, probably hundreds of years before, the continuity of strata, until then on the same plane, had been broken, leaving a fissure where the drop had taken place.
There was no means of estimating the extent of the vertical displacement, but the boy was satisfied that it was the difference between the height of the range at the place where the cavern opened and the height to the north, probably three hundred feet or more.

The north end of the range had dropped down.