The water, beautifully transparent, permitted the eye to penetrate into its green depths for many fathoms around, though every object presented, through the agitated surface, an uncertain and fluctuating outline. I could see, however, the pink-colored urchin warping himself up, by his many cables, along the steep rock-sides; the green crab stalking along the gravelly bottom; a scull of small rock-cod darting hither and thither among the tangle-roots; and a few large medusae slowly flapping their continuous fins of gelatine in the opener spaces, a few inches under the surface. Many curious families had their representatives within the patch of sea which the eye commanded; but the strange creatures that had once inhabited it by thousands, and whose bones still lay sepulchred on its shores, had none. How strange, that the identical sea heaving around stack and skerry in this remote corner of the Hebrides should have once been thronged by reptile shapes more strange than poet ever imagined,--dragons, gorgons and chimeras! Perhaps of all the extinct reptiles, the Plesiosaurus was the most extraordinary. An English geologist has described it, grotesquely enough, and yet most happily, as a snake _threaded_ through a tortoise. And here on this very spot, must these monstrous dragons have disported and fed; here must they have raised their little reptile heads and long swan-like necks over the surface, to watch an antagonist or select a victim; here must they have warred and wedded, and pursued all the various instincts of their unknown natures. A strange story, surely, considering it is a true one! I may mention in the passing, that some of the fragments of the shale in which the remains are embedded have been baked by the intense heat into an exceedingly hard, dark-colored stone, somewhat resembling basalt. I must add further, that I by no means determine the rock with which we find it associated to be in reality an altered sandstone. Such is the appearance which it presents where weathered; but its general aspect is that of a porphyritic trap. Be it what it may, the fact is not at all affected, that the shores, wherever it occurs on this tract of insular coast, are strewed with reptilian remains of the Oolite.