And as the ship advanced, the bold outline of a high and nearly perpendicular bluff revealed itself above the fog, and had the appearance of hanging directly over the ship.

There was no mistaking the danger now.

In a few minutes more the ship was between walls of rock three hundred feet high, drifting swiftly through a narrow channel of deep and agitated water into a dark and dangerous cavern.
The ship passed in under full sail; the atmosphere changed and became singularly oppressive; the very blood chilled; fear seized on all on board, and men who a short time before were full of courage and strength now became as helpless as children.

The current was less rapid inside, but the noise increased and became even more bewildering; while the barometer would rise and fall quickly, and the compasses became agitated under the influence of some strong magnetic disorder.

Every few minutes deep and rumbling sounds would break in the distance, roll along the cavern, and echo and reecho through the great arches overhead.