They had passed through a region of boiling geysers, where the water shot more than a hundred feet into the air, and came down in a rain, across which a beautiful rainbow formed, the roaring sound which accompanied this exhibition being as loud as the exhaust of a thousand locomotives.
In one marshy valley they had passed pools of water, sulphur yellow, bright green, pink, crimson, and nearly all colors of the rainbow, the pools being from twenty to fifty feet apart.
They had seen other things which were not given a second glance by Old Rocks, but which Frank longed to stop and examine.
But it was no time for sight-seeing, as the boy well knew, and he held close to the heels of the unwearying guide.
And now, near nightfall, Old Rocks declared that the trail was getting hot.
"Shall we be able to overtake them before dark?" asked Frank, with the greatest anxiety.
"I dunno," was the answer. "But it's derned certun thet we ain't goin' ter come fur from it."
"Oh, for two hours more of daylight!" sighed the boy.
"We'd run ther critters down dead sure in thet time. But I don't want yer ter git ther idee thet they're goin' ter give up ther gal 'thout a murmur."
"But they will have to give her up."