Ragnarok : the Age of Fire and Gravel. Ignatius Donnelly

mass, and is subservient to that all-pervading law of sympathetic gravitation that is the sustaining bond of the material universe. It is ponderable substance beyond all question, and held by that chain of physical connection which it was the glory of Newton to discover. If the comet were not a material and ponderable substance it would not gravitate round the sun, and it would not move with increasing velocity as it neared the mighty mass until it had gathered the energy for its own escape in the enhanced and quickened momentum. In the first instance, the ready obedience to the attraction, and then the overshooting of the spot from which it is exerted, combine to establish the comet's right to stand ranked at least among the ponderable bodies of space."[1]

      And it is to the comet we must look for the source of a great part of those vast deposits of gravel which go to constitute the Drift.

      "They have been usually attributed to the action of waves; but the mechanical work of the ocean is mostly confined to its shores and soundings, where alone material exists in quantity within reach of the waves and currents.[2] … The eroding action is greatest for a short distance above the height of half-tide, and, except in violent storms, it is almost null below low-tide."[3]

      But if any one will examine a sea-beach he will see, not a vast mass of pebbles perpetually rolling and grinding each other, but an expanse of sand. And this is to be expected; for as soon as a part of the pebbles is, by the attrition of the waves, reduced to sand, the sand packs around the stones and arrests their further waste. To form such a mass of gravel as is found in the Drift we

      [1. "Edinburgh Review," October, 1874, p. 202.

      2. Dana's "Text Book," p. 286.

      3. Ibid., p. 287.]

      {p. 79}

      must conceive of some way whereby, as soon as the sand is formed, it is removed from the stones while the work of attrition goes on. This process we can conceive of in a comet, if the finer detritus is constantly carried back and arranged in the order of the size of its particles.

      To illustrate my meaning: let one place any hard substance, consisting of large fragments, in a mortar, and proceed to reduce it with a pestle to a fine powder. The work proceeds rapidly at first, until a portion of the material is triturated; you then find that the pulverized part has packed around and protected the larger fragments, and the work is brought to a stand-still. You have to remove the finer material if you would crush the pieces that remain.

      The sea does not separate the sand from the gravel; it places all together at elevations where the waves can not reach them:

      "Waves or shallow soundings have some transporting power; and, as they always move toward the land, their action is landward. They thus beat back, little by little, any detritus in the waters, preventing that loss to continents or islands which would take place if it were carried out to sea."[1]

      The pebbles and gravel are soon driven by the waves up the shore, and beyond the reach of further wear;[2] and "the rivers carry only silt to the ocean."[3]

      The brooks and rivers produce much more gravel than the sea-shore:

      "The detritus brought down by rivers is vastly greater in quantity than the stones, sand, or clay produced by the wear of the coasts."[4]

      [1. Dana's "Text Book," p. 288.

      2. Ibid., p. 291.

      3. Ibid., p. 302.

      4. Ibid., p. 290.]

      {p. 80}

      But it would be absurd to suppose that the beds of rivers could have furnished the immeasurable volumes of gravel found over a great part of the world in the drift-deposits.

      And the drift-gravel is different from the gravel of the sea or rivers.

      Geikie says, speaking of the "till":

      "There is something very peculiar about the shape of the stones. They are neither round and oval, like the pebbles in river-gravel, or the shingle of the sea-shore, nor are they sharply angular like newly-fallen débris at the base of a cliff, although they more closely resemble the latter than the former. They are, indeed, angular in shape, but the sharp corners and edges have invariably been smoothed away. … Their shape, as will be seen, is by no means their most striking peculiarity. Each is smoothed, polished, and covered with striæ or scratches, some of which are delicate as the lines traced by an etching-needle, others deep and harsh as the scores made by the plow upon a rock. And, what is worthy of note, most of the scratches, coarse and fine together, seem to run parallel to the longer diameter of the stones, which, however, are scratched in many other directions as well."[1]

      Let me again summarize:

      I. Comets consist of a blazing nucleus and a mass of ponderable, separated matter, such as stones, gravel, clay-dust, and gas.

      II. The nucleus gives out great heat and masses of burning gas.

      III. Luminous gases surround the nucleus.

      IV. The drift-clays are the result of the grinding up of granitic rocks.

      V. No such deposits, of anything like equal magnitude, could have been formed on the earth.

      [1. "The Great Ice Age," p. 13.]

      {p. 81}

      VI. No such clays are now being formed under glaciers or Arctic ice-sheets.

      VII. These clays were ground out of the substance of the comet by the endless changes of position of the material of which it is composed as it flew through space, during its incalculable journeys in the long reaches of time.

      VIII. The earth-supplies of gravel are inadequate to account for the gravel of the drift-deposits.

      IX. Neither sea-beach nor rivers produce stones like those found in the Drift.

      I pass now to the next question.

      {p. 82}