THE CHAPTER VIII. THE FRONT OF THE PROCESSION OF LIFE. HE spirits have come forth. The life-giving afflatus has been breathed into multitudes of organic forms which now teem in the PALEOZOIC sea. 'Say, mysterious Earth! oh say, great Mother and Goddess! Was it not well with thee then, when first thy lap was ungirdled, The long period of almost total lifelessness-the Eozoic TIME—it will be remembered, was brought to a close by the upheaval of a long ridge of land, extending from the coast of Labrador to the northern shores of the great lakes, and thence northwest to the Arctic Sea. Corresponding upheavals took place on other continents. A convulsion could not jar one half the globe without being felt upon the other half, and hence it is that all the grand revolutions of geology were simultaneous, and the histories of different continents are divided into corresponding chapters. We confine our attention, however, to North America. The germinal ridge consists of an axis or nucleus of granitic material, and on each side of a series of gneissoid and other eozoic strata sloping like the roof of a house from the central and highest part. We know that this upheaval took place after the deposition of the eozoic strata, because those strata could not have been deposited in their present. D a tilted position (Fig. 19). We know that it took place before the deposition of the next series of strata, because ее .b Fig. 19. Disturbed condition of Eozoic Strata. a. Eozoic strata, tilted and contorted by disturbances occurring before the deposition of the Paleozoic strata, b, c, d. e, e, e. Faults or dislocations of Eozoic and Paleozoic strata, evidently of later date than the contortions of a. these strata were not tilted by the upheaval, but continue to present their horizontal edges against the inclined faces. of the eozoic beds. Thus the precise relative period of this upheaval is fixed. Consider the geography of the North American continent at this date. An angular ridge of land (Fig. 20) is all that а a מן Fig. 20. The Germ of the North American Continent. a, a. The two branches of the continent. b, b. Islands. (The modern continent is indicated by dotted lines, the rivers by broken lines.) then existed. The Rocky Mountains and the Alleghanies were not yet born from the deep. Where were the United States? Where the broad valley of the Mississippi, and the wide-extended plains of the far West? Beneath the wave, and receiving the sediments of the same sea which rolled over the future sites of Babylon, and Tyre, and Athens, and the seven hills of the "Eternal City." The generations of men yet slumbered in the chambers of futurity. The order of Providence had assigned them their position in the grand procession of life which was now beginning to move, and the scouts of which had passed by in the preceding age; but we must wait for man till a long line of grotesque and marvelous forms has marched before our view. The van of this procession was led by some of the humbler forms of God's creation. We shall indeed look in vain for a type of existence of simpler mould than the Laurentian Eozoön. It is likely that beings akin to this accompanied the shoals of higher forms which sprang into existence at the morning dawn of the Silurian Age. But if they lived, the record of their existence has been effaced from the earth. Like the deeds and the sufferings of the men who kept company with the extinct quadrupeds of Europe, and chased the fur-clad mammoth across the steppes of Siberia, their very existence is reached only by conject ure, and the activities which made up life with them have all been locked up with the arcana of the past. The creatures whose relics we have disentombed were more highly gifted than the Eozoön, and were launched into being under a great variety of forms. The oldest Silurian rocks of North America are perhaps those revealed to science upon the island of Newfoundland by the assiduity of the Canadian geologists. Their records have been recently studied by the paleontologist Billings, of Montreal, an investigator eminent for acuteness and for the importance of his paleon tological discoveries. An assemblage of strata named by him the "St. John's Group" is described as underlying rocks that had heretofore been regarded as forming the very base of the Silurian system in America. These St. John's strata may probably be regarded as inclosing the remains of the first considerable fauna that ever lived within the limits of America. Our knowledge of these primeval relics is as yet very imperfect*, being limited to one crinoid, two brachiopods, and half a dozen genera of trilobites. Though they mark generally a great simplicity of organization, one can not but be astonished that in the very outset of animalization upon our globe so high a rank and so great variety of types should have been manifested. If we are to judge from that which is known rather than that which is conjectured, we are compelled to conclude that the varied forms of animal life did not come into being by a gradual evolution from the Eozoön, but as so many original ut Fig. 21. Paradoxides Harlani (X%). St. terances of the all-skilled Ar John's Trilobite. tificer of creation. Of the "Potsdam group" of strata [see Appendix, Note III.], and the organic remains which they inclose, we have learned somewhat more. The "Potsdam sandstone" at the * Billings (E.): "Catalogues of the Silurian Fossils of the Island of Anticosti," p. 79. bottom of the group, was long regarded as the oldest fossiliferous rock in America. It is certainly not far from the lowest horizon of the primeval cemeteries which hold the dust of the first denizens of our planet. This sandstone is sometimes whitish or grayish, but often of a dull red color, and sometimes slaty; and except within the area covered by the St. John's group, it is found resting upon the upturned edges of the Eozoic strata. Observe that it is a sandstone. Now we know that in the waters of the present day, sands are accumulated only in comparatively turbulent and shallow regions. In calmer and deeper waters, the sediments are necessarily finer, as only the finest particles can be transported by the slowest moving currents (compare Fig. 15). Moreover, many a layer of this ancient Fig. 22. Cliffs of Potsdam Sandstone on the sandstone, when uncovered to the light, presents us with veritable ripple marks-such as the waves are making to-day in the fine sand of the shallow water near the beach-sandripples which have been preserved unmarred for millions of years, and unite with other proofs. that the bottom of the Protozoic sea was not beneath the reach of the agitations of its surface. This interesting sandstone was first attentively studied at Potsdam and Keeseville, in |