Ragnarok : the Age of Fire and Gravel. Ignatius Donnelly

Чтение книги онлайн.

СКАЧАТЬ to conceive of a glacier upon the bare top of a mountain, without walls to restrain it or direct its flow, or higher ice accumulations to feed it.

      Again:

      "If glaciers descended, as they did, on both sides of the great Alpine ranges, then we would expect to find the same results on the plains of Northern Italy that present themselves on the low grounds of Switzerland. But this is not the case. On the plains of Italy there are no traces of the stony clay found in Switzerland and all over Europe. Neither are any of the stones of the drift of Italy scratched or striated."[2]

      [1. "The Great Ice Age," p. 73.

      2. Ibid., pp. 491, 492.]

      {p. 22}

      But, strange to say, while, as Geikie admits, no true "till" or Drift is now being formed by or under the glaciers of Switzerland, nevertheless "till" is found in that country disassociated from the glaciers. Geikie says:

      "In the low grounds of Switzerland we get a dark, tough clay, packed with scratched and well-rubbed stones, and containing here and there some admixture of sand and irregular beds and patches of earthy gravel. This clay is quite unstratified, and the strata upon which it rests frequently exhibit much confusion, being turned up on end and bent over, exactly as in this country the rocks are sometimes broken and disturbed below till. The whole deposit has experienced much denudation, but even yet it covers considerable areas, and attains a thickness varying from a few feet up to not less than thirty feet in thickness."[1]

      Here, then, are the objections to this theory of the glacier-origin of the Drift:

      I. The glaciers do not produce striated stones.

      II. The glaciers do not produce drift-clay.

      III. The glaciers could not have formed continental sheets of "till."

      IV. The glaciers could not have existed upon, and consequently could not have striated, the mountain-tops.

      V. The glaciers could not have reached to the great plains of the continents far remote from valleys, where we still find the Drift and drift-markings.

      VI. The glaciers are limited in number and confined in their operations, and were utterly inadequate to have produced the thousands of square miles of drift-débris which we find enfolding the world.

      [1. "The Great Ice Age," p. 373.]

      {p. 23}

      CHAPTER VI.

      WAS IT CAUSED BY CONTINENTAL ICE-SHEETS?

      WE, come now to the theory which is at present most generally accepted:

      It being apparent that glaciers were not adequate to produce the results which we find, the glacialists have fallen back upon an extraordinary hypothesis--to wit, that the whole north and south regions of the globe, extending from the poles to 35° or 40° of north and south latitude, were, in the Drift age, covered with enormous, continuous sheets of ice, from one mile thick at its southern margin, to three or five miles thick at the poles. As they find drift-scratches upon the tops of mountains in Europe three to four thousand feet high, and in New England upon elevations six thousand feet high, it follows, according to this hypothesis, that the ice-sheet must have been considerably higher than these mountains, for the ice must have been thick enough to cover their tops, and high enough and heavy enough above their tops to press down upon and groove and scratch the rocks. And as the striæ in Northern Europe were found to disregard the conformation of the continent and the islands of the sea, it became necessary to suppose that this polar ice-sheet filled up the bays and seas, so that one could have passed dry-shod, in that period, from France to the north pole, over a steadily ascending plane of ice.

      No attempt has been made to explain where all this

      {p. 24}

      ice came from; or what force lifted the moisture into the air which, afterward descending, constituted these world-cloaks of frozen water.

      It is, perhaps, easy to suppose that such world-cloaks might have existed; we can imagine the water of the seas falling on the continents, and freezing as it fell, until, in the course of ages, it constituted such gigantic ice-sheets; but something more than this is needed. This does not account for these hundreds of feet of clay, bowlders, and gravel.

      But it is supposed that these were torn from the surface of the rocks by the pressure of the ice-sheet moving southward. But what would make it move southward? We know that some of our mountains are covered to-day with immense sheets of ice, hundreds and thousands of feet in thickness. Do these descend upon the flat country? No; they lie there and melt, and are renewed, kept in equipoise by the contending forces of heat and cold.

      Why should the ice-sheet move southward? Because, say the "glacialists," the lands of the northern parts of Europe and America were then elevated fifteen hundred feet higher than at present, and this gave the ice a sufficient descent. But what became of that elevation afterward? Why, it went down again. It had accommodatingly performed its function, and then the land resumed its old place!

      But did the land rise up in this extraordinary fashion? Croll says:

      "The greater elevation of the land (in the Ice period) is simply assumed as an hypothesis to account for the cold. The facts of geology, however, are fast establishing the opposite conclusion, viz., that when the country was covered with ice, the land stood in relation to the sea at a lower level than at present, and that the continental periods or times, when the land stood in relation to the

      {p. 25}

      sea at a higher level than now, were the warm inter-glacial periods, when the country was free of snow and ice, And a mild and equable condition of climate prevailed. This is the conclusion toward which we are being led by the more recent revelations of surface-geology, and also by certain facts connected with the geographical distribution of plants and animals during the Glacial epoch."[1]

      H. B. Norton says:

      "When we come to study the cause of these phenomena, we find many perplexing and contradictory theories in the field. A favorite one is that of vertical elevation. But it seems impossible to admit that the circle inclosed within the parallel of 40°--some seven thousand miles in diameter--could have been elevated to such a height as to produce this remarkable result. This would be a supposition hard to reconcile with the present proportion of land and water on the surface of the globe and with the phenomena of terrestrial contraction and gravitation."[2]

      We have seen that the surface-rocks underneath the Drift are scored and grooved by some external force. Now we find that these markings do not all run in the same direction; on the contrary, they cross each other in an extraordinary manner. The cut on the following page illustrates this.

      If the direction of the motion of the ice-sheets, which caused these markings, was,--as the glacialists allege,--always from the elevated region in the north to the lower ground in the south, then the markings must always have been in the same direction: given a fixed cause, we must have always a fixed result. We shall see, as we go on in this argument, that the deposition of the "till" was instantaneous; and, as these markings were made before or at the same time the "till" was laid down, how could the land

      [1. "Climate and Time," p. 391.

      2. "Popular Science Monthly," October, СКАЧАТЬ