Look up! Didn't I tell ye so ?" Wilder drew back out of the narrow aperture, through which he had been craning his neck and shoulders in order to get a view of what was passing above.
The hole leading into the grotto that held them was barely large enough to admit the body of a man.

Hamersley took his place, and, turning his eyes upward, at once saw what his comrade referred to.

It was the smoke of a fire, that appeared in the act of being kindled near the edge of the aperture above.

The smoke was ascending towards the sky, diagonally drifting across the blue disc outlined by the rim of rock.
He had barely time to make the observation when a swishing sound admonished him to draw back his head; then there passed before his face a ruck of falling stalks and faggots.

Some of them settled upon the ledge, the rest sweeping on to the bottom of the abyss.
In a moment after the shaft was filled with smoke, but not that of an ordinary wood fire.