know that an ancient river-bed stretches from Lake Michigan down through the valley of the Illinois. The subterranean explorations of the well-borer's auger have disclosed multitudes of ancient gorges which are now filled up with drift. If such tremendous gorges were ever cut, they were filled up and obliterated by the great glacier. And may not this reparation of the surface have been one of the beneficent operations of the glacier? We are told no glacial action is detected west of the Rocky Mountains. Had the great glacier been moved over the deep-cut gorges of the great desert, they must have been filled and blotted out, and the new-formed streams, on the advent of man, would have been just in the act of surveying new channels for themselves. The bare rock would have been clothed with soil, and the "desert" might have been the garden of the continent. CHAPTER XXXII. PRIMEVAL MAN. HE history of our race, traced back a few thousand TH years, loses itself in traditions and myths. We come down out of a cloud of obscurity, in which we can just discern the rude forms of men clad in skins, frequenting the caves of wild beasts, fashioning rude pottery, and practicing in the chase with the primeval bow and arrow. of the haze which hangs over the verge of antiquity come sounds of conflict in arms, pæans of peace, hymns to relig ion, and the hum of barbaric industry. Out Our written history does not extend back to the origin of man. The Mosaic records, which are undoubtedly the oldest of our authentic documents, represent the western. portion of Asia as swarming with a population tolerably advanced in the arts at a period two or three thousand years antecedent to our era. There was, consequently, a long interval of human history still anterior to this date. What destinies befell our race-how did they live, whither did they wander, during that prolonged infancy of which-Revelation aside-we have no other information than such as we have gleaned of the Mastodon, the Megatherium, or the Zeuglodon? The quickened intellectual activity of the modern age has started new and interesting inquiries in this direction. There are no questions which more profoundly interest us than the history of primeval man. The investigation has been pushed far beyond the limits of the most ancient written documents. It has passed over the remoter domain of archæology and stepped upon the ground consecrated to the researches of geology. The chief sources of our information respecting the earliest periods of human history are, 1st. The remains of man himself, which have been found in caves or buried in deposits of gravel or peat. 2d. Human works, of which we have the so-called Druidical remains of Great Britain and other countries, known as dolmens or cromlechs-rude megalithic monuments of unhewn stone, which we now know to be ancient tombs. Other human works more abundant and more universally distributed are implements of war, of the chase, of industry, or of ornament. These are found in gravel-beds along the valleys of rivers or at their mouths; in peat beds; in caves, and among the refuse piles contiguous to the camping or dwelling-places of tribes which subsisted partly upon molluscs. These refuse heaps are composed mostly of shells of recent species, bones of domestic or wild animals suitable for food or service, fragments of pottery, arrow-heads, fish-hooks, stone implements, ornaments, and the like. A vast supply of the relics of primeval man has been obtained from the pile-habitations, or ancient dwellings constructed upon platforms supported by piles driven in the water. The dredging of the bottoms of these lakes has brought to light immense quantities of the remains of pre-historic art and industry. 3d. The manner in which the relics of man are associated with those of other animals enables us to extend to our race many of the generalizations deduced in reference to the earlier history of the existing fauna. Lastly, the nature and magnitude of the geological changes which have transpired during the existence of man throw some light upon the antiquity of the race. As in the history of organic life in general, so in the geological history of man, we find him mounting from lower |