Ocean floor

“ My mind, with loosely-hanging sails,
Lies waiting the auspicious gales.
On either side, behind, before,
The ocean stretches like a floor,—
A level floor of amethyst,
Crowned by a golden dome of mist. ”

“ In general the floor is extremely irregular with several 20- to 40-fathom "hills" per mile. The floor is covered by sediment which transmits sound so readily that the area is noted for exceptionally pronounced sub-bottom reflections from the rock layers beneath the sediment.
Northeastern United States Sector.—From the northeast tip of Georges Bank to Cape Hatteras the continental margin is remarkably uniform in morphologic detail. ”

“ It appears as if only the old ocean-floor is in a position to form deeps, because its cooling and hardening extend down to a greater depth. Perhaps they may be considered as marginal rifts, one side of which is formed of the sial of the festoons, and the other of the sima of the deep-sea floor. The profile of this area, shown in Fig. 26, in reality very flat, need not lead one astray, for naturally it is strongly levelled down by gravity. ”

“ It is separated from the ocean floor by a low outer ridge which rises 100-500 fathoms above the level of the adjacent ocean floor. The bottom of a trench is generally rugged except near the deepest spots where it is flat. ”

“ The ocean floor, as has been well remarked, with its uniformity in the matter of temperature, food, station and general conditions of life, contains, in fact, no effectual barriers to the almost indefinite dispersal of species.
The following general conclusions with regard to the deep-sea fauna were arrived at after working out the material and evidence obtained during the cruise of H.M.S. "Challenger":— (1) Animal-life is present at all depths on the ocean floor. (2) At extreme depths life is not nearly so abundant as at moderate depths ”

“ I dream of a day when they may rise above the billows to drag down in their reeking talons the remnants of puny, war-exhausted mankind—of a day when the land shall sink, and the dark ocean floor shall ascend amidst universal pandemonium. ”

“ The ocean-basin floor lies between the continental margin and the Mid-Oceanic Ridge and consists of the deeper abyssal floor and the elevated oceanic rises. On the abyssal floor adjacent to the continental margins are found the flattest surfaces of the earth. These abyssal plains apparently were built by turbidity-current deposits. The unburied abyssal floor is represented by the abyssal hills. The oceanic rises are broad uplifts which rise from the abyssal floor through a series of scarps. Oceanic rises are covered with pelagic sediments except locally near islands and seamounts. ”

“ The shelving floor of the ocean rises nearly to the surface along this line, and vast colonies of coral building creatures have formed their reefs up to the water's edge along the ridge. The turbulent waves scouring over this living mass have carved and moulded it into millions of fantastic islands, sometimes heaping detached masses of dead debris high above the surface of the water. ”

“ Where a coast land emerges the—shore line moves seaward; where it is being submerged the shore line advances on the land.
Shores of elevation. The retreat of the sea, either because of a local uplift of the land or for any other reason, such as the lowering of any portion of ocean bottom, lays bare the inner margin of the sea floor. Where the sea floor has long received the waste of the land it has been built up to a smooth, subaqueous plain, gently shelving from the land. ”

“ Definition and distribution.—An oceanic rise is a large area (measured in hundreds of miles) , not connected to or included in a mid-oceanic ridge or connected to a continental rise, which rises a few hundred fathoms above the surrounding abyssal floor. The topography of an oceanic rise ranges from gentle to extremely rugged. ”

“ Since the bottom of the sea forms the great receptacle into which the mouldered remains of the surface of the land are continually carried, it is plain that if this state of things were to go on without modification or hindrance, in the end the whole of the solid land would be worn away, and its remains would be spread out on the sea floor, leaving one vast ocean to roll round the globe. ”

“ But if no foreign matter be introduced, the buildings, when once removed to a depth where the action of the waves is insensible, and where no great current happens to flow, may last for indefinite periods, and be as durable as the floor of the ocean itself, which may often be composed of the very same materials. ”

“ Although sand and gravel are distributed over the bottom of the ocean near the land, dredging expeditions reaching down their metal cylinders for samples of the sea-floor at greater depths in various sections of the globe, have discovered that it is of a different composition, one-third of its area being covered with red clay. ”

“ If we make a general comparison with the surface of the land, the floor of the ocean is a vast monotonous plain. None of the sea bottom compares with the ruggedness of mountains, and even the more level portions of land surface show many sharp minor irregularities such as stream trenches. ”

“ The surface of each of our ocean floors exactly resembles that of a continent turned upside down. Taking the Atlantic as our simplest type, we may say that the surface of an ocean basin resembles that of a mighty trough or syncline, buckled up more or less centrally in a medial ridge, which is bounded by two long and deep marginal hollows, in the cores of which still deeper grooves sink to the profoundest depths. ”

“ Seen from the Table-Rock, the tumbling green waters of the rapids, which persuade you that an ocean is approaching, the brilliant color of the water, the frightful gulf, and headlong torrent at your feet, the white column rising from its centre, and often reaching to the clouds, the black wall of rock frowning from the opposite island, and the long curtain of foam descending from the other shore, interrupted only by one dark shaft, form altogether one of the most beautiful, as well as awful scenes in nature. ”

“ No mere surf breaking on sand could have compassed so deep and multitudinous a voice of dreadful roaring—far out over the entering tide, yet at the same time close in along the entire sweep of shore, shaking all the ocean, both depth and surface, with its deep vibrations. Into the bungalow chamber came—the Sea! ”

“ From the beach, a little below the foot of the tower, seaward, as far as the eye could reach through the mist and spray, the ocean tossed and rolled. Great hills of water, green and angry, rose as though pushed up from below, their crests lashed into foam and then blown into vapor by the gale; wave succeeded wave, until a mighty host of waters, rank on rank, impelled by the wind, dashed themselves to foam on the ever-resisting shore. ”

“ The sun throws a ray of light through, the mottled sky; the sea rolls sluggishly; porpoises are sporting about, now throwing themselves into the air, and now rushing into schools of flying-fish which are frightened from their element and pursued by the albatross. As we approach still nearer, immense rocks tower up from the margin of the ocean, some rising to the height of one hundred feet, some being columns of granite, presenting an appearance as uniform as if cut by the hand of man. ”

“ Again quoting Sir Archibald Geikie:—"The materials carried down to the sea would arrange themselves then as they do still, the coarser portions nearest the shore, the finer silt and mud furthest from it. From the earliest geological times the great area of deposit has been, as it still is, the marginal belt of sea-floor skirting the land. It is there that nature has always strewn the dust of continents to be." ”

“ Even the floor itself on which we stand, and the vegetation it puts forth, are unlike those of any other portion of the earth’s surface, and may well recall, by their strange appearance in the half light, the fancies that have come upon us when we have read or dreamt of those gifted beings, who, like Ladurlad in Kehama, could walk on the floor of the sea, without waiting, as the visitors at Watering-places are obliged to do, for the tide to go out. ”

“ The iron roof, lofty but exceedingly low-browed, so that a woman must stoop to enter, is supported externally on pillars of coral, within by a frame of wood. The floor is of broken coral, divided in aisles by the uprights of the frame; the house far enough from shore to catch the breeze, which enters freely and disperses the mosquitoes; and under the low eaves the sun is seen to glitter and the waves to dance on the lagoon. ”

“ Solid as the ground appears, all is subject to elemental change and motion; and whenever the waves of the sea or the strong current of a river can plough some crumbling chine, or wear away the face of a cliff, down come the imbedded pebbles and crystals, and gradually form a beach upon the margin of the ocean. ”

“ At every season of the year the solid piers of the ground floor have the yellow tone and the imperceptible sweating surface that moisture gives to stone. The passer-by feels chilled as he walks close to this wall, where worn corner-stones ineffectually shelter him from the wheels of vehicles. ”

“ The area protected by the sea wall, as low as the sea level, was covered all over with long, rank grass. At the north end of the islet a curious round rock, exactly like a martello tower, but rather higher, rose out of the water, separated from the sea wall by twenty or thirty feet of deep water, dark blue, transparent; sometimes rolling and rushing and tearing at the sides of the rock, sometimes gently lifting the sea-weed that clung to the sides. Round the top of the rock flew, screaming, all the year round, the sea birds. ”

“ Not only barriers and reefs owe their origin to these humble means, but large lands, stretching for miles in the centre of the ocean, rise gradually from beneath the surface of the sea, and, becoming clothed with verdure and vegetation, at last offer a resting-place for the daring seafarer. ”

“ On this view every difficulty vanishes; fringing reefs are thus converted into barrier-reefs; and barrier-reefs, when encircling islands, are thus converted into atolls, the instant the last pinnacle of land sinks beneath the surface of the ocean. ”

“ The rock rises out of the sea with perpendicular sides of marble, and only in one spot is to be observed a natural opening made by the water, hardly two feet high, through which the boat passed at once into a spacious court, almost circular, and over-arched by the sky, the floor of which was covered by the sea, and adorned with a garden of corals. ”

“ But also the powerful attraction of the land, particularly of great mountain ranges, lifts the sea-surface in some regions hundreds of feet higher than in others. So that a ship, passing from the neighbourhood of a mountainous coast to [p. 128] mid-ocean, may be actually sailing or steaming downhill, actually descending a vast gentle watery slope.
Another question as to Ocean’s level has much exercised the minds of men.
Throughout the world, remains of sea-creatures in countless multitudes are found embedded in the substance of water-built rocks: sometimes the very rocks being made up of them. ”

“ If we stand on almost any shore of the world as it exists at present, and consider the character of the land surface on the one hand, and of the ocean bottom on the other, we shall see that a very great difference in the nature of the beach line would be produced by a depression of the land towards the ocean, or by an elevation of it from the deep. ”

“ As we advanced, the rocky ceiling overhead was closing down on us, until soon there was no more than twice the length of our bodies between it and the floor.
On both sides the dark water stretched out as far as we could see into blackness also. We were descending now at an angle of perhaps forty-five degrees.
We had gone what you would call a mile possibly, when we came suddenly to a tangle of coral—a barrier that reached from floor to ceiling. ”

“ You must fancy yourself in the middle of the great ocean, and you will perceive that there is an almost circular island, with a low beach, which is formed entirely of coral sand; growing upon that beach you have vegetation, which takes, of course, the shape of the circular land; and then, in the interior of the circle, there is a pool of water, which is not very deep—probably in this case not more than eight or nine fathoms—and which forms a strange and beautiful contrast to the deep blue water outside. This circular island, or atoll, with a lagoon in the middle, is not a complete circle ”

“ It is evident, then, that between the floor of the sea and the surface of the land, there must be this great difference: that whereas the land is undergoing a continual destruction of its surface, from mountain crest to sea shore, the sea bottom, on the other hand, is constantly receiving fresh materials on its surface. The one is increased in proportion as the other is diminished. ”

“ The stupendous columnar side walls—the depth and strength of the ocean with which the cavern is filled—the variety of tints formed by stalactites dropping and petrifying between the pillars, and resembling a sort of chasing of yellow or cream-coloured marble filling the interstices of the roof—the corresponding variety below, where the ocean rolls over a red, and in some places a violet-coloured rock, the basis of the basaltic pillars—the dreadful noise of those august billows so well corresponding with the grandeur of the scene—are all circumstances elsewhere unparalleled. ”

“ With the larger ones we make islands and archipelagos on our floor while the floor is a sea, or we make a large island or a couple on the Venice pattern, or we pile the smaller on the larger to make hills when the floor is a level plain, or they roof in railway stations or serve as bridges, in such manner as I will presently illustrate. ”