Читать книгу Walks and Talks in the Geological Field - Alexander Winchell - Страница 25

“The sea! the sea!” shouted the companions of Balboa, as they caught the first glimpse of the Pacific from the heights of the American Isthmus. The sea has always inspired the wonder—often the veneration—of mankind. Its vastness and power overwhelm the imagination. Its permanence, its antiquity, form a bewildering conception. The same “far-sounding sea” roared in the hearing of the mariners of the remotest past. The same ocean floated the ships of the Tyrians and Carthaginians. Its mysterious depths aroused the superstitions of the ancients as they excite the intelligent curiosity of modern science. A “glorious mirror,” as Byron conceived it,

“Where the Almighty’s form Glasses itself in tempests.**** Boundless, endless, and sublime, The image of eternity—the throne Of the invisible.”

Let us stand on some bold headland and look out over the Atlantic. Let us plant ourselves on Sankaty Head, the eastern promontory of Nantucket, itself the “ultima Thule” of New England. The breakers roar along the beach. Across the billowy blue thought wanders to the European shore. Underneath the ruffled surface imagination pictures a world of curious and wonderful existences. There lie the skeletons of noble ships—there moulder the dead sailors of all nations—there rot invaluable cargoes—there sleep the mysteries of steamers which sailed out of sight of land and never returned—there swarm the sharks that desecrate the sacred forms of humanity which sink into their silent empire. Shall we venture among the dangers of the under-world? Yes, we invoke the magic protection which has made warriors invulnerable, and shielded adventurers upon the waters of Styx, and the fiery waves of Phlegethon.

We go down like bathers in the sea. We pass the margin where

“The dreary black seaweed lolls and wags.”

We traverse the borders where the brown, belted kelp sways to and fro in graceful curves. We get beyond the slope of stony bottom to the smooth sand. We come to the gardens of the rosy-tinted sea-mosses—the Dasya, the Grinnellia, the Callithamnion; and startle the blue-fish and halibut in their safe seclusion. A moonlight gleam is here, and the water also takes on the chill of evening. We pass on, and attain a depth of half a mile. Our feet press into the finer sediments derived from the land—the dust of other “continents to be.” The twilight has faded into a deep shade. The creatures of the sea swarm curiously about us, then flee in terror from our presence. We feel the gentle movement of “a river in the ocean,” but the surface disturbances do not reach even to this depth. A change of climate impresses itself on our sensations. The water where we started in had a temperature of sixty degrees—here it is forty. But we are panoplied against harm; we press on. We descend to the depth of a mile under the sea. The curiously gazing species of the shallower water appear no more. Their home is the zone which now stretches above our heads. The green and rosy sea-mosses never venture here. We are in total darkness; no chlorophyll tints the growths of the vegetable kingdom. Here are only stony, white calcareous algae and silicious diatoms of microscopic minuteness.

We pause to contemplate the awful stillness of the submarine realm, and feel our slimy path down to the deeper profound. Above us now float two miles of black sea. Any surface fish brought down here perishes from the effect of enormous pressure, if possessing an air-bladder. If it have none, the fish becomes torpid, and finally dies. We are here, probably miles from the shore—that varies with the steepness of the slope. The sediments which the rivers have brought to the ocean have mostly been deposited between our starting point and this. But here still are some of the finest particles contributed by the land—slime from Louisiana, from Chautauqua, from the Rocky Mountains, from our native town. Will these far-brought and commingled atoms ever see daylight again?

We are standing on the border of the vast abyss which extends over half the area of the earth. It is an undulating, silent desert. No diversity of mountain and valley, cliff and gorge exists. We have read of submarine cliffs and plateaus, but these are known only in the shallower ocean; they are features of the continental slope. By a gentle grade the bottom descends to a depth of five miles. Over all this dread waste, no rocks rise above the bed of slime. No fragments of crystalline rocks have been brought up by the dredge. A thousand miles away the bottom has been burst through by an internal force, and lavas have heaped themselves up to the height of a mile or two, or even to the actual surface; but no upheaval has brought to light from the abysmal floor any trace of those hard crystalline rocks which we recognize as “metamorphic”—the sort of which our bowlders are formed. There is no evidence that such rocks were ever produced in that situation.

The pressure on us in this abysmal region is four or five tons to every square inch. The water is ice-cold everywhere. The darkness, absolute and palpable. A curdling revulsion of feeling and purpose seizes us. We halt and reflect. We turn our eyes upward with a painful longing for the “holy light, offspring of heaven first-born.” Only the black ceiling appears. Two miles above us is the sunny sea, where all the blue of a genial sky beams down. There float the ships in summer calm upon a “painted ocean,” or tossed and rent by the winter tempest which inspires the waves with madness. But no summer and winter vicissitudes are here. No sunlight ever penetrates this Cimmerian gloom. No sunrise, or noonday, or sunset is ever known. As it was when the Garden of Eden was first consecrated to man, so it has remained and must remain. Not even the crash of thunders or the roar of tempests can be heard. The huge wave, crested with elemental fury, rolls on, but makes no stir in the stillness and stagnation of the abysmal realm.

When we crossed the borders of this dark and silent abyss, our feet sank in a white pasty slime which has been designated “Globigerina ooze.” The dredges of the Challenger and the Albatross have been down here, hung by a piano wire over the stern of the vessel, and samples of this ooze have been studied. We find it composed chiefly of microscopic dead shells called Fo-ram-i-nif´-e-ra, together with others called Pter´-o-pods. The little creatures which formed the shells do not live here; they dwell in calm zones of water far above. When the conscious animal ceases to live, its tiny house sinks down into this dark world. And thus, as the ages roll by, the fine chalky rain slowly accumulates upon the bottom. When this ooze is dried and hardened, it resembles the chalk of Europe; and when that is microscopically examined, we find in it the same little Foraminifera. These are important geological facts, which, though they come out of an abyss of darkness, throw a vivid light on equally dark chapters of the world’s long-past history.

We have groped our way down three and four miles beneath daylight. A sort of ooze still overspreads the bottom; but it is not the Globigerina and Pteropod ooze. It is a fine rusty clay. But the white shells are not wanting because the tiny creatures which secrete them are not overhead. They swarm there as elsewhere, far from land with other pelagic forms. But the fragile matter of the shell is dissolved before it reaches this great depth. Only the aluminous and insoluble constituent reaches the bottom. This clay ooze possesses other interest. Disseminated through it are minute crystals of such minerals as escape through the throats of volcanoes into the upper air. Here are the dust particles which have imparted a ruddy glow to many a past sunset. Once the source of the roseate glory of the twilight hour, they lie now, in impenetrable darkness and the repose of death. How changed the fortune of the little particle. It floated for months in the upper thin air—in the film of space which separates earth from heaven—borne hither by the simoon, thither by the anti-trades, hurled in the vortex of a cyclone and precipitated in mid-ocean by a down-falling mass of vapor. Then, perhaps, seized by the waves, and rocked and beaten at the surface till it reached a zone of calm, it began its silent descent into the dark world where it is destined to rest undisturbed for centuries.

Here too is cosmic dust. The seeds of worlds have been sprinkled through space, and some of them have been planted in the soil of this abyss. These minute globules of magnetic iron were sparks emitted from a burning meteor. The meteor was a small mass or particle of material stuff coursing swiftly through the cold interplanetary spaces. It pierced the atmosphere of the earth; the friction resulting ignited the meteor, and for a brief moment it painted a fiery streak in its flight, when all had been transformed to ashy particles which floated in the air like volcanic dust, until it found, at last, a resting place in the cold bed of the Atlantic. What a reversal of fortune was here! The particle might have swept on through space, as many of its companions did, until it became part of a glowing comet. Perhaps it once shone in a star—now it is dead for a cycle of ages. It is an impressive thought that here, in this rayless night, we find the black ruins of a star. The realities of material history exceed in wonder all the fictions of imagination.

We still stand wondering over the scene which surrounds us. How oppressive is this silence. How welcome would be the cheerful chirp of the sparrow. Even the piping of the hated mosquito would break the eternal monotony. From age to age this reign of death persists. A chill which is more than icy, pierces us to the marrow. Sometimes, as we grope through the Egyptian gloom, we kick the bones of aquatic creatures which have perished in the water above us. Often their kind is still in existence; but sometimes their species are long extinct. Here are teeth of sharks and ear-bones of whales which have lain during geologic ages. Grand vicissitudes have passed by, which transformed the aspect of continents, but these relics lay here undisturbed—unburied—so slowly do the sediments accumulate.

But there is indeed life here. Sparse, quaint life; and the species are of archaic and embryonic forms; that is, they resemble creatures which lived in the earlier ages of the world, or creatures which have undergone but a part of their development—crude, uncouth, and alien to the modern world. Here are Crinoids, or Stone Lilies, which, in all other waters, have perished from the earth—save one species long known in the Caribbean Sea. They are an antique type. But from deep waters off the coasts of Florida and Norway, comes up, with other forms, Rhiz-oc´-ri-nus, a genus which disappeared from shallow seas unknown millions of years ago; but here, where nothing changes, it has perpetuated its existence through half the history of the world. Between death and the changeless life which here reigns, the difference is slight.

Still more startling in their grotesqueness, are some of the fishes which lie here more than half buried in the mud. Here is one fashioned like a scoop-net. The long, slender body is the handle, and the net is an enormous pouch under the chin, which would take in the whole of the body three times over. Another hangs like an open wide-mouthed meal-bag. In this case, also, the bag hangs suspended from the part where the throat should be. The diminutive body is noticed as an appendage attached to the back side of the bag. It is known by the fins. Four of these bodies might be contained in one pouch. A different, but equally erratic form brandishes an attenuated body like a whip-lash appended to an enormous head, exposing an eye which is nearly half its own diameter. Still again, we note a shark-like form, with enormous gape and horrid teeth, having a range of spines along each side of the slender body, above and below, and, most curious of all, a long, thread-like organ depending from beneath the chin, with a tassel-like tentacle bearing structures for feeling, at the end. Indeed, this reminds us of the piano wire with dredge at the end, which went feeling for examples from this so-called bassalian fauna, and brought up the very prototype of its own mechanism.

But see! somebody is here with a lantern. How sleepily the light gleams in the darkness. There is no fire in it. Something it is. An animated lantern. A lantern without a flame. It is another strange fish. It is phosphorescence which gleams mildly from his shiny sides. Still another lantern-bearing fish. Here are luminous plates beneath the eyes; behind them, in a cavity, retinal tissue, as if these structures were planned for eyes; but they are not eyes. Real eyes are present. We discover, then, faint relief from the palpable darkness in which we have groped.

But our task is done; our curiosity is gratified; we have glimpsed the underworld, and have gathered observations on which we shall ponder many a day. Let us now, like the heroes of epic song, ascend to the light of the upper world.