“Yes,” replied the American coolly; “there’s gold in the rock up yonder by the water, and I found this in one little hole.”

He took a scrap of yellow metal from his pocket, and held it out to the doctor.

“A nugget of gold,” said that gentleman, “very much worn by the water.”

“And the stones,” said Griggs sharply; “and no wonder, for it was being swept round and round. One minute I could see it, the next it was gone; but it was washed right into my hand at last. I dare say we might wash a good deal here.”

“But you do not propose to stop?”

“No, sir; I’ve an idea that this is the most likely part we’ve come to yet. Let’s get on. We could come back then if we found nothing better.”

Griggs’ remarks roused the interest of all present, and at the end of half-an-hour, spent by the boys in washing the sand in a pool lower down, where they found a few scales of the rich metal, the journey was continued, Griggs leading, to where all further progress seemed impossible, for they were compelled to halt by the apparent closing-in of the gorge, which presented, in fact, an unclimbable precipice. A few steps farther there was a narrow rift extending from their feet to the top of the cliff a couple of thousand feet above their heads, and literally doubling back into this, they threaded their way along a passage not twenty feet in width, which zigzagged here and there for about a quarter of a mile deeper and deeper into the mountains, growing more and more gloomy, and then all at once displaying the bright glow of sunshine right in front, as if it came round an elbow of the way. A few minutes later Griggs led the party into a vast amphitheatre walled in by towering walls that were on the whole perpendicular, but seamed with rifts running up to natural terraces or breaks in the strata of which the vast walls were composed.

The change from the gloom of the zigzag ravine along which they had made their way, to the sunlit amphitheatre, was almost painful, and the party stood in a group shading their eyes, gazing about in silence, till Chris suddenly snatched off his hat, waved it in the air, and with a shout startled the mules into the beginning of a stampede.

But this was nipped in the bud, and as soon as the animals were calmed down, the boy cried excitedly—

“I didn’t mean to do that. But, I say, we’ve found the old city at last.”