See that line of breakers just below the horizon? That shows where Father Neptune is serving the little coral people with food and fresh air, as explained in the text.
We know also that the sea makes coal as well as stone in its rock mills; that the pressure of the overlying rock was in large part the source of the heat that changed the vegetation of the swamps, first into charcoal and then into coal.
The subject of what the sea has done and is doing for us is almost as endless as the seas themselves; and no doubt the reason the sea is never still is because it has so much to do. Nothing in earth's animate or inanimate nature exercises an influence to be compared in importance to that of the sea, not only upon the land, but upon the whole life which land and sea support; and even in what seem to be the most aimless of its movements it in reality acts with the precision of a machine.
III. The Artist
And in the making of the rock in its presses under the water, as well as in the grinding which takes place along the shores, the sea evidently has an eye to beauty as well as use. As originally formed, the conglomerates or "pudding-stones" are always laid nearest the shore because there the retiring waves and the rivers emptying into the sea drop the heaviest part of their load, including the pebbles. Next is dropped the sand which is pressed into sandstone and beyond this the finest particles of all, the ground-up soil, which becomes slate rock. Still beyond the zone of slate is deposited the lime from the shells of sea creatures who can live only in this clearer water, away from the muddy waters nearer the shore. These deposits make limestone. The result of this natural sorting process is that all the four kinds of sedimentary rock are always laid down in just this 1, 2, 3, 4 order and no other: (1) pudding-stone; (2) sandstone; (3) slate; (4) limestone.
Then, as a result of the transgressions of the sea, what was once a region of conglomerate may be later found far out under the sea and there is thus laid down over the conglomerate beds, strata of sandstone, slate, or limestone, depending on how far the sea advances. So we find rocks with all sorts of neighbors above and below; limestone above conglomerate, conglomerate above slate. These changes take place over vast regions and from the original uniformity in the arrangement of the rocks there necessarily results a similar uniformity in the results of this "shuffling," and no matter what changes may be made afterward by raising them up into shore cliff and mountain and by other earth movements, and by the endless reshaping by weather and wave, there still remains that underlying harmony which, with variety, gives to rocky shores their picturesque beauty.
Harmony and variety are necessary in all forms of art—pictures, literature, music—and the conditions governing harmony and variety are always found hand-in-hand in the art work of the sea and its helpers. The difference in texture in different kinds of rock, for example, and in different parts of the same rock, cause them to yield in different ways and degrees to the action of wave, wind and weather; so there is sure to be great variety in the shapes they take as they are worn away.
HARMONY, VARIETY, AND THE ART WORK OF THE SEA FAMILY LIKENESS IN ROCK FORMS
Yet, with all their differences, the shapes rocks take—sandstone compared with granite, for example—are so characteristic that one soon learns to tell a long way off what kind of rock a distant landscape is made of. There is inevitably a certain type resemblance, since all sandstone is of the same general texture and weathers in the same way.
NATURE'S BUILDING BLOCKS AND THE SEA