There was nothing visible.

He paused, with his ear toward the water, his face full of frightened expectation.

Ha! There came a single plashing sound, like some great beast slipping into the river, and little waves in a wide semi-circle came out from under the bank and spread over the water! "My God!" He plunged down the levee and bounded through the low weeds to the edge of the bank.

It was sheer, and the water about four feet below.

He did not stand quite on the edge, but fell upon his knees a couple of yards away, wringing his hands, moaning and weeping, and staring through his watery eyes at a fine, long crevice just discernible under the matted grass, and curving outward on either hand toward the river.
"My God!" he sobbed aloud; "my God!" and even while he called, his God answered: the tough Bermuda grass stretched and snapped, the crevice slowly became a gape, and softly, gradually, with no sound but the closing of the water at last, a ton or more of earth settled into the boiling eddy and disappeared.
At the same instant a pulse of the breeze brought from the garden behind, the joyous, thoughtless laughter of the fair mistresses of Belles Demoiselles.
The old Colonel sprang up and clambered over the levee.