Yaqui mounted and wheeled Diablo away. The others followed. Gale saw that the plateau was no more than a vast field of low, ragged circles, levels, mounds, cones, and whirls of lava. The lava was of a darker red than that down upon the slope, and it was harder than flint. In places fine sand and cinders covered the uneven floor. Strange varieties of cactus vied with the omnipresent choya. Yaqui, however, found ground that his horse covered at a swift walk.

But there was only an hour, perhaps, of this comparatively easy going. Then the Yaqui led them into a zone of craters. The top of the earth seemed to have been blown out in holes from a few rods in width to large craters, some shallow, others deep, and all red as fire. Yaqui circled close to abysses which yawned sheer from a level surface, and he appeared always to be turning upon his course to avoid them.

The plateau had now a considerable dip to the west. Gale marked the slow heave and ripple of the ocean of lava to the south, where high, rounded peaks marked the center of this volcanic region. The uneven nature of the slope westward prevented any extended view, until suddenly the fugitives emerged from a rugged break to come upon a sublime and awe-inspiring spectacle.

They were upon a high point of the western slope of the plateau. It was a slope, but so many leagues long in its descent that only from a height could any slant have been perceptible. Yaqui and his white horse stood upon the brink of a crater miles in circumference, a thousand feet deep, with its red walls patched in frost-colored spots by the silvery choya. The giant tracery of lava streams waved down the slope to disappear in undulating sand dunes. And these bordered a seemingly endless arm of blue sea. This was the Gulf of California. Beyond the Gulf rose dim, bold mountains, and above them hung the setting sun, dusky red, flooding all that barren empire with a sinister light.

It was strange to Gale then, and perhaps to the others, to see their guide lead Diablo into a smooth and well-worn trail along the rim of the awful crater. Gale looked down into that red chasm. It resembled an inferno. The dark cliffs upon the opposite side were veiled in blue haze that seemed like smoke. Here Yaqui was at home. He moved and looked about him as a man coming at last into his own. Gale saw him stop and gaze out over that red-ribbed void to the Gulf.

Gale devined that somewhere along this crater of hell the Yaqui would make his final stand; and one look into his strange, inscrutable eyes made imagination picture a fitting doom for the pursuing Rojas.

The trail led along a gigantic fissure in the side of the crater, and then down and down into a red-walled, blue hazed labyrinth.

Presently Gale, upon turning a sharp corner, was utterly amazed to see that the split in the lava sloped out and widened into an arroyo. It was so green and soft and beautiful in all the angry, contorted red surrounding that Gale could scarcely credit his sight. Blanco Sol whistled his welcome to the scent of water. Then Gale saw a great hole, a pit in the shiny lava, a dark, cool, shady well. There was evidence of the fact that at flood seasons the water had an outlet into the arroyo. The soil appeared to be a fine sand, in which a reddish tinge predominated; and it was abundantly covered with a long grass, still partly green. Mesquites and palo verdes dotted the arroyo and gradually closed in thickets that obstructed the view.