Bang! Bang! Bang! came the explosions.
Instantly, Mr. Merrill and Bud wheeled their horses sharply and faced round toward the danger. At the same instant Coyote Pete set up a yell:
"Buncoed, by ginger!"
He pointed ahead as he dashed across the bridge in pursuit of their treacherous guide, who was galloping off up the cañon at top speed. He had taken advantage of the confusion to escape. Without an instant's thought as to what they were doing, the three boys pressed spurs to their animals and thundered across the flimsy structure after the cow-puncher. The professor's horse became unmanageable in the excitement. The creature gave one tremendous plunge and with the unhappy scientist half on and half off its back, dashed across the bridge after the others.
In the meantime, Mr. Merrill and the cow-punchers had galloped back to where the firing still kept up. They all feared that they had been led into an ambush, and that the attack was from the rear.
"That yellow-skinned varmint betrayed us, after all," ground out Bud Wilson, as they dashed back. "Those shots were meant for us, and came from Black Ramon's men."
"Yes, we were wrong to trust him," rejoined Mr. Merrill, "but now we've been led into a trap, we've got to fight out of it the best way we can."
"You bet we will, boss," was Bud Wilson's rejoinder.
The firing on the hillside had now ceased, and the little cavalcade came to a halt.