"Hi lee! Hi lo!
Hi lee! Hi lay!—--"
The "perfusser," as Cal insisted on calling him, had obligingly begun when from ahead of them and high up, as it seemed, came a peculiar sound.
It was a crackling of brush and small bushes apparently. Instinctively Nat stopped the car and it was well that he did so, for the next instant a giant boulder came crashing down the steep mountainside above them.
Instinctively Nat stopped the car, and it was well that he did so, for the next instant a giant boulder came crashing down.
CHAPTER XIII.
THE VOLLEY IN THE CANYON.
Nat had stopped in the nick of time. As the auto came to an abrupt halt, almost jolting those in the tonneau out of their seats, there was a roar like the voice of an avalanche. From far up the hillside a cloud of dust grew closer, and thundered past like an express train. In the midst of the cloud was the huge, dislodged rock, weighing perhaps half a ton or more.
So close did it whiz by, in fact, just ahead of the car, that Nat could almost have sworn that it grazed the engine bonnet. The ground shook and trembled as if an earthquake was in progress, during the passage of the huge rock.