From what he said it could not be far off, but they were disappointed before reaching the right point.

A gradual descent of the sides was notable, and continued until the depth of the canyon was decreased one-half, while the roar became more audible.
"We can't be far from the break," said Jack; "that is, if this descent continues." They found, however, a few minutes later, that it did not continue, but began to increase, until they were fully as elevated above the bottom of the gorge as at the point where they had leaped it.

The width also varied continually, sometimes being only three or four feet, while in others it expanded to nearly ten times that extent.

They did not pause to look over the margin again, for their aim was to reach the place referred to by their friend.
At the moment when they began to wonder whether a mistake had not been made they came upon the break.

Both banks sloped downward so abruptly that it would have been laborious for the two to work their way to the bottom, or from the bottom to the top, though the masses of boulders, with the tough pines growing almost the whole distance, offered secure foothold.
The picture was an interesting one.