And Milton speaks from the same universal inspiration when he tells us : "A comet burned, That fires the length of Ophiucus huge In th' arctic sky, and from its horrid hair And in the Shakespeare plays* we read: "Hung be the heavens with black, yield day to night! Comets, importing change of times and states, Brandish your crystal tresses in the sky; And with them scourge the bad revolting stars." Man, by an inherited instinct, regards the comet as a great terror and a great foe; and the heart of humanity sits uneasily when one blazes in the sky. Even to the scholar and the scientist they are a puzzle and a fear; they are erratic, unusual, anarchical, monstrous-something let loose, like a tiger of the heavens, athwart an orderly, peaceful, and harmonious world. They may be impalpable and harmless attenuations of gas, or they may be loaded with death and ruin; but in any event man can not contemplate them without terror. CHAPTER VII. THE EARTH STRUCK BY COMETS MANY TIMES. If the reader is satisfied, from my reasoning and the facts I have adduced, that the so-called Glacial Age really represents a collision of the earth with one of these wandering luminaries of space, the question can not but occur to him, Was this the first and only occasion, during all the thousands of millions of years that our planet has been revolving on its axis and circling around the sun, that such a catastrophe has occurred? The answer must be in the negative. We find that all through the rocky record of our globe the same phenomena which we have learned to recognize as peculiar to the Drift Age are, at distant intervals, repeated. The long ages of the Paleozoic Time passed with few or no disturbances. The movements of the earth's crust oscillated at a rate not to exceed one foot in a century.* It was an age of peace. Then came a tremendous convulsion. It has been styled by the geologists "the epoch of the Appalachian revolution." "Strata were upraised and flexed into great folds, some of the folds a score or more of miles in span. Deep fissures were opened in the earth's crust," like the fiords or great rock-cracks which accompanied the Diluvial or Drift Age. "Rocks were consolidated; and over some parts sandstones and shales were crystallized into gneiss, Dana's "Text-Book," p. 150. mica-schist, and other related rocks, and limestone into architectural and statuary marble. Bituminous coal was turned into anthracite in Pennsylvania." * I copy from the same work (p. 153) the following cut, showing the extent to which the rocks were crushed out of shape: SECTION ON THE SCHUYLKILL, PENNSYLVANIA. P, Pottsville on the coal-measures; 2, Calciferous formation; 3, Trenton; 4, Hudson River; 5, Oneida and Niagara; 7, Lower Helderberg; 8, 10, 11, Devonian; 12, 13, Subcarboniferous; 14, Carboniferous, or coal measures. These tremendous changes were caused by a pressure of some kind which came from the east, from where the Atlantic Ocean now rolls. "It was due to a lateral pressure, the folding having taken place just as it might in paper or cloth under a lateral or pushing movement." t "It was accompanied by great heat, which melted and consolidated the rocks, changed their condition, drove the volatile gases out of the bituminous coal and changed it into anthracite, in some places altered it to graphite, as if it had been passed through a furnace." It also made an almost universal slaughter of all forms of life: "The extermination of life which took place at this time was one of the most extensive in all geological history; . . . no fossils of the Carboniferous formation occur in later rocks." # * Dana's "Text-Book," p. 152. + Ibid., p. 155. # Ibid., p. 157. It was accompanied or followed, as in the Drift Age, by tremendous floods of water; the evaporated seas returned to the earth in wasting storms: "The waters commenced the work of denudation, which has been continued to the present time."* Is not all this a striking confirmation of my theory? Here we find that, long before the age of man, a fearful catastrophe happened to the earth. Its rocks were melted-not merely decomposed, as in the Drift Age,-but actually melted and metamorphosed; the heat, as in the Drift Age, sucked up the waters of the seas, to cast them down again in great floods; it wiped out nearly all the life of the planet, even as the Drift Age exterminated the great mammals; whatever drift then fell probably melted with the burning rocks. Here are phenomena which no ice-sheet, though it were a thousand miles thick, can explain; here is heat, not ice; combustion, not cold; and yet all these phenomena are but the results which we have seen would naturally follow the contact of the earth with a comet. But while, in this particular case, the size of the comet, or its more fiery nature, melted the surface of the globe, and changed the very texture of the solid rocks, we find in the geological record the evidences of repeated visitations when Drift was thrown upon the earth in great quantities; but the heat, as in the last Drift Age, was not great enough to consume all things. In the Cambrian formation, conglomerates are found, combinations of stones and hardened clay, very much like the true "till." In the Lower Silurian of the south of Scotland, large blocks and bowlders (from one foot to five feet in diam *Dana's "Text-Book," p. 156. eter) are found, "of gneiss, syenite, granite, etc., none of which belong to the rocks of that neighborhood." Geikie says: "Possibly these bowlders may have come from some ancient Atlantis, transported by ice.”* The conglomerates belonging to the Old Red Sandstone formation in the north of England and in Scotland, we are told, "closely resemble a consolidated bowlder drift."† Near Victoria, in Australia, a conglomerate was found nearly one hundred feet in thickness. "Great beds of conglomerate occur at the bottom of the Carboniferous, in various parts of Scotland, which it is difficult to believe are other than ancient morainic débris. They are frequently quite unstratified, and the stones often show that peculiar blunted form which is so characteristic of glacial work.” ‡ Professor Ramsay found well-scratched and blunted stones in a Permian conglomerate. In the north of Scotland, a coarse, bowlder-conglomerate is associated with the Jurassic strata. The Cretaceous formation has yielded great stones and bowlders. In the Eocene of Switzerland, erratics have been found, some angular and some rounded. They often attain great size; one measured one hundred and five feet in length, ninety feet in breadth, and forty-five feet in height. Some of the blocks consist of a kind of granite not known to occur anywhere in the Alps. Geikie says: "The occurrence in the Eocene of huge ice-carried blocks seems incomprehensible when the general character of the Eocene fossils is taken into account, for these have a somewhat tropical aspect. So, likewise, the appearance of ice-transported blocks in the Miocene is a sore puzzle, + Ibid., p. 479. + Ibid. "The Great Ice Age," p. 478. |