IV
THE TWIN SLABS
Within half an hour the gig had reached the mouth of the cave. As the coxswain had predicted, the seas ran into the lofty entrance. Elsewhere the surf fell whitely, but through the arch the waves rolled unbroken into a heavy stillness. Only as the boat hovered for a moment at the face of the cliff could the exploring party hear, far within, the hollow boom that told of breakers on a distant, subterranean beach.
"Run her in easy," came the captain's order. "Keep a sharp lookout for hidden rocks."
To the whispering plash of the oars they moved from sunlight into twilight, from twilight into darkness. Of a sudden the oars jerked convulsively. A great roar had broken upon the ears of the sailors; the invisible roof above them, the water heaving beneath them, the walls that hemmed them in, called, with a multiplication of resonance, upon the name of Darrow. The boat quivered with the start of its occupants. Then one or two laughed weakly as they realised that what they had heard was no supernatural voice. It was the captain hailing for the marooned man.
No vocal answer came. But an indeterminable space away they could hear a low splash followed by a second and a third. Something coughed weakly in
230
