The opening was at first a narrow tunnel in the cliff, but after some yards it began to widen gradually, and at length enlarged itself into a spacious vault, in which there was a continuous murmur, such as is heard on putting a shell to one’s ear. By the time the boys reached it the tide had completely left the cave, and the boat stranded on a sandy beach, littered with rocks of all shapes and sizes, which had apparently fallen at various times from the roof. They lit their lantern, whose yellow rays fell on jagged granite walls, glistening shells, and slimy seaweed covering the rocks on the floor. Here and there were small pools which the tide never left dry, and where the light of the lantern revealed innumerable little marine creatures darting this way and that with extraordinary rapidity. The boys made the boat fast by looping the painter round a jagged boulder. They moved warily, for the seal was a beast unknown to either of them, though Dick, in his total ignorance of these creatures of the deep, hardly expected to find them in the cave now that the sea had receded. Presently, however, they heard above the hollow murmur another sound, like the feeble bleat of a very young lamb. They peered about, moving the lantern to and fro, and at length discovered, lying on a rocky ledge at the inmost end of the cave, two small cream-coloured objects, scarcely more than a foot long, whose soft eyes blinked in the light, and from whose mouths issued plaintive cries of alarm. "Bean’t they proper little mites!" said Sam, putting out his hand to touch them. "Don’t do that!" cried Dick hastily; "the old ones may be about, and if they’re like other beasts, they’ll attack us if they think we’ll hurt their young." "Shan’t we take ’em, then?" asked Sam. "Of course not; they’re too young." "And shan’t we look for the old uns?" "No; the young ones would die if we killed the parents. We must come again later on, when they’re old enough to take care of themselves. But our day shan’t be wasted. We’ll see if we can find the other entrance to the cave." "What other entrance?" "Your father says ’tis thought that at one time there was a way in from an adit above." "I can’t believe it. The free-traders would have found it long afore this if so ’twere." "I don’t know. The adit wouldn’t be an easy passage for them with their bales and kegs. But don’t let us waste time; the tide will be running back soon." They followed the irregular circuit of the cave, thrusting the lantern into every recess and hollow, holding it high and low, but discovering nothing except the same rugged and apparently impenetrable wall. "There bean’t no opening," said Sam at length. "’Twas fiddle-faddle to say there be." "Perhaps it is high above us, out of reach," suggested Dick.