"They're here!" cried Floyd, when it became very evident that an attack in force was going on.

"Oh! I'm glad!" exclaimed Rosemary, and tears of relief came to sooth her ragged nerves.

They went as close as they dared to the mouth of the cave to look at the backs of the Yaquis who were lined up along the wall firing down on the soldiers and cowboys. No guard was stationed at the entrance to the cavern—none was needed. The rear was a wall of solid rock, as Rosemary and her brother had discovered soon after being rushed into it. In front of the entrance was a rocky platform, and extending along the outer edge of this, in the form of a semicircle, was the defending wall of stone.

This rocky wall dropped abruptly down into the defile where the cowboys and soldiers were making the attack. It would be almost impossible to descend it. The way up was by a narrow passage which was now choked by rocks the Indians had piled there.

On either side of the cavern's entrance the rock rose in steep slopes, not altogether impossible of being scaled, but a hindrance to a quick retreat. That is what Captain Marshall meant when he said the Yaquis were practically backed up against a stone wall.

The firing became sharper and quicker and the reports of the guns of the attackers sounded nearer. They were, in fact, creeping up, taking advantage of every bit of cover.

There were casualties on both sides, Dick being put out of the game by a bullet through his right arm. Fortunately it only entered the flesh, breaking no bones. But he was ordered to the rear, much to his disgust. Nort and Bud still stuck, Bud helping Nort in loading.

Perhaps the situation was hardest on Rosemary and Floyd, for they were obliged to remain in the cave, doing nothing, and fearing the worst. If the Indians succeeded in standing off the rescuers, or in killing so many of them that the survivors would not dare rush the place, what would it mean to the captives?

Rosemary dared not think of it.

Then, following a period of unusually heavy firing, the plucky girl made up her mind to act.