“Most interesting, most interesting,” breathed the Professor.  “But how comes it that this level stretch of fertile land is found in this rugged, rocky canyon, Nance?”

“That’s easily answered.  During hundreds of years the river has deposited vast quantities of marl at the upper ends of this valley.  Thus four great dams have been built up forming barriers across the canyon.  These dams have quite largely filled up, leaving level stretches of land of great richness.”

“Do they work the land?” asked Tad.

“In a primitive way, they do, probably following the methods they learned from the cliff dwellers, who occupied the crude dwellings you have seen all along these walls in the canyons here.”

The Cataract Canyon proved to be the most interesting of all that the boys had seen for variety and beauty.  The Havasu River, foaming in torrents over Supai and Navajos Falls, fifty and seventy-five feet high, respectively, they found gliding through a narrow canyon for half a mile, in a valley matted with masses of trees, vines and ferns, the delicate green of whose foliage contrasted wonderfully with the dead gray walls of the deep, dark canyon at that point.

For some three miles below this the Pony Riders followed the smoothly-gliding stream through a canyon whose straight up and down walls of gray limestone seemed to meet overhead in the blue of the sky.  Below they seemed to be in the tropics.  During that first day in the Cataract they saw another wonder, that of the filmy clouds settling down and forming a roof over the Canyon.  It was a marvelous sight before which the Pony Rider Boys were lost in wonder.

The Bridal Veil Falls they thought the most beautiful wonder of its kind they had ever seen.  Here they saw the crystal waters dashing in clouds of spray through masses of ferns, moss and trees, one hundred and seventy-five feet perpendicularly into a seething pool below.

Their delight was in the innumerable caves found along the Canyon.  In these were to be seen flowers fashioned out of the limestone, possessing wonderful colors, scintillating in the light of the torches, reds that glowed like points of fire, stalactites that glistened like the long, pointed icicles they had seen hanging from the eaves of their homes in Chillicothe.  They discovered lace-work in most delicate tints, masses and masses of coral and festoons of stone sponges in all the caves they visited.  There were little caves leading from larger caves, caves within caves, caves below caves, a perfect riot of caves and labyrinths all filled with these marvelous specimens of limestone.

“I think I would be content to live here always,” breathed Tad after they had finished their explorations of the caves and passed on into a perfect jungle of tropical growth on their way to Ko-ho-ni-no, the canyon home of the Havasupais.

“You’d never be lonesome here,” smiled Nance.