Fjords Of Scandinavia
( Originally Published 1881 )
Their Walls and Terminal Valleys.—Action of Glaciers. Terraces, or Sea-beaches.—Phenomena and Causes.—Shore-lines and Sea-marks. —Rising and Sinking of the Land in Modern Times.—Cannot be used as a Measure of Time.--Professor Kjerulf's Views on the Subject.—Iceberg and Glacier Theories.—Unequal and Intermittent Movements, and Long Periods of Rest.—Changes in Climate, and in the Distribution of Plant and Animal Life.
As one sails along the peninsula of Scandinavia, and especially on the coast of Norway, he sees everywhere the deep narrow arms of the sea winding their way, often a hundred miles, amidst the masses of rock 'belonging to the oldest formations; these arms of the sea are called fjords. Those of Norway are far larger and more majestic than those of Sweden, and partake of the grandeur of the scenery characteristic of the country. As you gaze in admiration, almost with awe, at their walls, towering thousands of feet above the sea, the question naturally arises, What are the causes which have formed these wonderful channels? As the sea has no sweep adequate to produce them, the second thought might naturally be that some great convulsions of nature have led to their formation ; but neither the sea nor geological catastrophes have been active agents in this case.
Invariably at the end of a fjord there is a valley, with a stream collecting the water from the mountain -sides ; these valleys are in all respects the continuation of the fjord, only one is land, the other water, and both are cut out of the solid rock; the same is true of the branch or transverse fjords and dales.
Everywhere you see the grooving, striation, and polishing due to the action of ice; numerous moraines, so extensive that they are often covered with farms, fields, and hamlets; every-thing shows that the fjords, like the valleys, have been scooped out of the solid rock by the action of glaciers. Looking at the immense height of these walls, and adding the great depth, which is often equal to the height of the mountains, we cannot comprehend the vast periods of time that must have been requiredby the glaciers to do this work on their slow but irresistible march to the sea; and we get an idea, which nothing else can give us, of the tremendous power of water, in the form of ice, in modifying the surface character of the globe.
To this day there are in Norway glaciers at the upper end of the fjords coming down to the sea, silent but unimpeachable witnesses of the work they have accomplished, and are still continuing; as they retire, month after month, they leave on the rocks precisely the same marks which they did ages ago. Time, frost, and atmospheric agencies have obliterated in many places these ice-marks, and often the dirt and debris of centuries hide them from the common eye, while preserving them for the geologist.
Sailing along the fjords, the openings of the valleys, or the sheltered bays of the Norwegian coast, the attention of the traveller cannot fail to be attracted by the terraces, or sea beaches, rising one over the other in amphitheatre form, looking like broad gigantic steps. They suggest at once successive risings of the land, and different, more or less permanent, levels of the sea, into which the rivers and streams have carried down stone, gravel, sand, and clay, and spread them beneath the surface.
In many of the fjords are short steep valleys, whose en-trance is barred by a terrace or two, surmounted by the blocks, stones, and sand of a moraine left by the preceding Glacial period; there are many lakes thus produced, following the course of the valley. The highest terrace, distinguishable from the moraine by its stratification, marks the oldest sea-level. Their height depends on the width of the valley, the amount of material deposited, and the duration of the subsidence ; the oldest reach a height of 600 to 620 feet, and contain marine arctic fossils. Marine shells, and shell banks of two distinct faunae, are also found in the clay. In the hard clay marls have been discovered skeletons of seals and fishes, and large peat beds occur in the plains. The lower and more recent terraces, from 50 'to 150 feet high, contain fossils belonging to the present faunae of regions below the polar circle on the coast of Norway. Immense banks of marine shells run parallel with the coast, and over them is a dark mould, as at Bodo. Other peat beds also occur below these later terraces.
Shore-lines, composed of cobble-stones, are met in different parts of the country; I have seen them on the northern shores of the Baltic, in the midst of coniferous forests, three in number, one above the other; also on the coast of Finmarken, back of Vadso.
Sea-marks are seen on several points of the coast of Norway. I have particularly noticed them near the city of Trondhjem, where they are found at a height of 462 to 516 feet ; near Stenso, on the Stavanger fjord; in Oster fjord, 138 feet above the sea; and also in Alten fjord. These marks do not correspond exactly with the height of the surrounding terraces, and must have been produced by the action of the waves, and would be much more common had not time and frost obliterated them in many places. The terraces, the shore-lines, and the sea-marks point to the great rising of land during the so-called "Terrace epoch," and to long periods of repose. But, if the above-mentioned facts indicate the upheaval of land just be-fore the present era, there is also proof that there has been in some districts a subsequent local sinking. There are several distinct submerged steep beaches on the island of Gotland, at a distance from the present cliffs, which, owing to the clearness of the water, can be distinctly seen from the shores.
Observations have been made in Sweden for a number of years, in the Baltic, by inserting marks in the rocks, which show that the land in the northern part rises about two and a half feet in a century, while it is sinking in the southern. There is a remarkable ridge along this sea, from Ystad to Trelleborg and Falsterbo, no doubt produced by the sudden rising of the land in the north and the sinking in the south, accompanied by an immense movement of the ocean; this ridge would cause a wide sea between Southern Scandinavia and Northern Germany. Anterior to this these two portions of land were connected as a continuous continental area, across which plants, animals, and man migrated; the southern part being the lowest, the northern, still covered with ice, would be the first occupied by man—probably by a race of hunters.
As far as present data are concerned, all attempts to approximate closely to the number of years required to produce these results are unsatisfactory, as the uprising and sinking movements have been found unequal, and indeterminable periods of almost perfect repose or very slow upheaval have intervened. Estimates based upon modern observation show only that a vast period of time must have elapsed, without giving us any positive information.
The theory of the uninterrupted movement of the land, and consequently the calculations based by some geologists on the upheavals as a measure of time, have been denied by the eminent geologist, Theodor Kjerulf, Professor of Geology in Christiania, and author of the best geological map of Norway. His theory is set forth in a discourse on " The Upheaval of Scandinavia Considered as a Measure of Time," delivered at the meeting of the Scandinavian naturalists at Copenhagen, in July, 1873, as follows, in a condensed form : "It is beyond dispute that the Scandinavian peninsula, at any rate in Sweden, is rising irregularly, but with extreme slowness : that a similar elevation has taken place in geological times, is clearly shown by the marine shells, clays, sands, skeletons of whales, terraces and shore-lines now seen at considerable heights above the present level of the sea, and at a distance inland." And again lie says, "The highest marks on the mountains or in the valleys are the dividing lines on the dial of time, denoting the beginning of fresh movements ; the hand is the present change of mutual level between land and sea." According to the iceberg theory of the glacier epoch—which, though as a whole unsatisfactory, must be called in to explain, in addition to the glacier theory, some of the phenomena on the borders of continents, and especially in Scandinavia--this peninsula sank down slowly under the arctic ice, the surfaces beneath were scored and grooved by the submerged and grounded bergs, and then the land slowly rose again to its present level. Accordingly., the measure of the present upheaval is, on an average, 2--feet in a century, or 600 feet in 24,000 years; as the groovings are found to the height of 6000 feet, the time required would be 240,000 years; and, as the theory demands a double movement—a sinking and a rising, each of 6000 feet—we have 480,000 years required, and this On the supposition that the movement has been uninterruptedly equal. But this has not been the case; proofs are innumerable in Norway that there have been relatively quick movements alternating with comparatively long rests—in other words, unequal and intermittent movements. The fact that the drift contains no marine fossils; the uniform direction of the grooves, as a rule, and their immense numbers; and that a depression would have caused a warmer, and not a colder climate, are in favor of the glacial, and against the iceberg theory. The oldest shell-banks, containing fossils of a more arctic character than the present, are all high—about 500 feet above the sea; there are more recent ones, with fossils like those now living, between 100 and 150 feet above the sea : they are not found at all levels, but only at a few and certain ones. We see, in fact, "steps of movement, and relative times of repose, under which those mighty masses of shells were heaped up on the coast at a certain level, and a start of movement may have followed."
As to the terraces in the valleys, no open-lying ones are seen more than 600 feet above the sea-level, being made from the materials brought down by the rivers. Had the movement been uninterruptedly equal, there would have been formed a continuously declining plane instead of terraces ; these last "are witnesses of a step, or start, in the movement; after that follows the relative rest." They extend only to the height of 600 feet, above which the groovings are made by glaciers, not by icebergs, so that no doubling movement is required, and no period of 480,000 years, but only 24,000 years, corresponding to an upheaval of 600 feet. "If we subtract," says the professor, "the height of the steps themselves, which express the proportionally quick change of level, and retain only the slowly declining, and apparently almost horizontal surfaces which mark the intermittent times of probable gradual rise, there remains but a fraction, a very small fraction, of this time." Strand-lines, the signs of the beach engraved, as it were, on the mountain-side, depend only on the stationary surface of the sea, while the terraces depend on the level of the sea, and the amount of materials transported down the watercourses, and on more rapid changes—these are distinct from each other. He thinks the geological time to the Glacial period cannot be more than 24,000 years, as the highest level belongs to the Arctic Sea. " This movement has gone on in steps, perhaps with weaker and weaker starts, till the present time."
On the island of Torgô rises the famous Torghatten to a height of 760 feet, having a natural tunnel 350 to 400 feet above the sea-level; its height varies from 64 to 289, and its width from 36 to 88 feet. The power that could have re-moved such a mass of stone must have been the sea. There are similar tunnels on Moskenaeso, Gryto, and Senjen.
The changes of climate are as wonderful. All over Scandinavia—even in the part beyond the arctic circle and North Cape—the fossils show unmistakably that at the close of the Tertiary period the polar regions enjoyed a temperate climate, as warm as that of England and France; ferns, conifer, oak, chestnut, and other forest trees once flourished on Spitzbergen, Beeren Island, etc.; and these, now frozen, lands presented features of soil and temperature which rendered them fit for the sustenance of terrestrial mammals, and for man, if he then lived in that part of the world.
After the Tertiary period the elevation of the land brought on a Glacial era, during which the forests gradually disappeared, and the animals moved southward; the climate became colder and colder, vegetation ceased, and, without means of subsistence, most animal life disappeared, leaving only the rein-deer, musk-ox, and a few other arctic species, which may have been witnesses of the Glacial period. Even these, should the glaciers increase southward, must move to milder regions or perish.