Perhaps slow currents have carried elsewhere the bodies of men who went down with the ship. Or perhaps the bones have succumbed already to the destructive working of ocean-waters. Or perhaps all on board were saved, when the gallant vessel sank. Let us hope that it was so. We are leaving the sticky ooze and getting into a region of stiff clay. If there were light enough, we should find it to be of a reddish tint. Here we do find bones--remains of creatures of a higher class, though not of man, the highest of all. Here are sharks’ teeth in great abundance, and many earbones of whales. Not much, after all, but something that tells of Life. Another lofty mountain height under water, rising from the ocean-bed. Shall we climb it, and see whither it may lead us? Have we not had enough of these black mysterious depths? Now up and up, cautiously feeling our way and using any such glimmers of living light as we come across. By-and-by we find ourselves getting into shallower water. Evidently this sub-ocean mountain approaches near to the surface. It will not end, like the last, a mile or more beneath. Here is a region of solid limestone rocks, made of reef-coral, which has been ground and pounded by the waves, and afterwards cemented firmly together. We are getting into levels where the waves have power. Presently the firm limestone is exchanged for coral mud, and later that gives place to reef-sand. By this time we have around us, not only living animals but living sea-weeds, which fact tells of our nearness to sunlight. It may still seem dark to us, but some light must be able to filter through, or plant-life could not exist. A few more fathoms of ascent, and we too are aware of light--dim and faint at first, yet steadily increasing. Shall we step out into the fresh air, the radiant sunshine, of a South-Sea coral island--into a world of light and life and beauty, all the fairer and the sweeter in its contrast with those gloomy under-ocean regions through which we have been wandering? CHAPTER XVIII. MULTITUDINOUS LIFE “This great and wide sea, wherein are things creeping innumerable, both small and great beasts.”--Ps. civ. 25. “The dense immensity Of ever-stirring Life, in thy strange forms Of fish and shell and worm and oozy mud.”--KINGSLEY. Some thirty or forty years ago the knowledge which man had of the “Great Deep” was practically _nil_. We know a good deal more now, thanks to the famous voyage of the _Challenger_, and to many other observations, though still the full sum of our information is small compared with the much that we do not know.