With what interest do we look upon any relic of early human history! The monument that tells of a civilization whose hieroglyphic records we cannot even decipher, the slightest trace of a nation that vanished and left no sign of its life except the rough tools and utensils buried in the old site of its towns or villages, arouses our imagination and excites our curiosity. Men gaze with awe at the inscription on an ancient Egyptian or Assyrian stone; they hold with reverential touch the yellow parchment-roll whose dim, defaced characters record the meagre learning of a buried nationality; and the announcement that for centuries the tropical forests of Central America have hidden within their tangled growth the ruined homes and temples of a past race, stirs the civilized world with a strange, deep wonder. To me it seems, that to look on the first land that was ever lifted above the wasted waters, to follow the shore where the earliest animals and plants were created when the thought of God first expressed itself in organic forms, to hold in one's hand a bit of stone from an old sea-beach, hardened into rock thousands of centuries ago, and studded with the beings that once crept upon its surface or were stranded there by some retreating wave, is even of deeper interest to men than the relics of their own race, for these things tell more directly of the thoughts and creative acts of God. The statement that different sets of animals and plants have characterized the successive epochs is often understood as indicating a difference of another kind than that which distinguishes animals now living in different parts of the world. This is a mistake. They are so-called representative types all over the globe, united to each other by structural relations and separated by specific differences of the same kind as those that unite and separate animals of different geological periods. Take, for instance, mud-flats or sandy shores in the same latitudes of Europe and America: we find living on each, animals of the same structural character and of the same general appearance, but with certain specific differences, as of color, size, external appendages, etc. They represent each other on the two continents. The American wolves, foxes, bears, rabbits, are not the same as the European. but those of one continent are as true to their respective types as those of the other; under a somewhat different aspect they represent the same groups of animals. In certain latitudes, or under conditions of nearer proximity, these differences may be less marked. It is well known that there is a great monotony of type, not only among animals and plants but in the human races also, throughout the Arctic regions; and some animals characteristic of the high North reappear under such identical forms in the neighborhood of the snow-fields in lofty mountains, that to trace the difference between the ptarmigans, rabbits, and other gnawing animals of the Alps, for instance, and those