[Illustration: Lign. 8:--Nautilus from the Chalk, near Lewes, (one-eighth the natural size.)] The Nautili were the contemporaries of the Ammonites, and many kinds are found associated with those shells, in strata far more ancient than the Chalk; and several species of both genera, as we have previously shown, were inhabitants of the cretaceous ocean. When the Ammonites became extinct, the Nautili continued to flourish, and numerous examples occur in the strata that were deposited during the vast period which intervened between the close of the Chalk formation, and the dawn of the existing condition of the earth's surface. At the present time two or three kinds only are known in a living state, and these are restricted to the seas of tropical climes, and so seldom approach the shores, that but few specimens of the animals that inhabit the shells have been obtained. The Nautilus, therefore, is one of those types of animal organization that have survived all the physical revolutions to which the surface of the earth was subjected during the innumerable ages that preceded the creation of the human race.[H] This remarkable fact is portrayed with much force and beauty by Mrs. Howitt, in the following stanzas: [H] Note IV. _Fossil Nautili._ TO THE NAUTILUS. Thou didst laugh at sun and breeze In the new created seas; Thou wast with the reptile broods In the old sea solitudes, Sailing in the new-made light, With the curled-up Ammonite. Thou surviv'dst the awful shock, Which turn'd the ocean-bed to rock; And chang'd its myriad living swarms To the marble's veined forms. Thou wert there, thy little boat, Airy voyager! kept afloat, O'er the waters wild and dismal, O'er the yawning gulfs abysmal; Amid wreck and overturning, Rock-imbedding, heaving, burning, Mid the tumult and the stir, Thou, most ancient mariner! In that pearly boat of thine, Sail'dst upon the troubled brine. [Sidenote: THE SEA-SHORE.] We have thus acquired satisfactory proof that the flint of which our pebble is composed, was once fluid in an ocean teeming with beings, of genera and species unknown in a living state, and that it consolidated and became imbedded in the chalk, which was then being deposited at the bottom of the sea; hence the shells, corals, and other organic remains, which we now find attached to its surface, and enclosed in its substance. Thus much for the origin of the pebble; let us next inquire by what means it was dislodged from its rocky sepulchre, cast up from the depths of the ocean, and transported to the summit of the hill whence it was dislodged by yonder torrent. If we stroll along the sea-shore, and observe the changes which are there going on, we shall obtain an answer to these questions; for There is a _language_ by the lonely shore-- There is society where none intrudes, By the deep Sea, and music in its roar! Byron.