Geological science, as well as revelation, impresses us with the belief that in the beginning "the earth was without form, and void,"--a chaos of atoms which were gathered, comet-like, from infinite space, and made to revolve in a globular mass by physical forces, until it became, by the condensation of its vapory atmosphere, submerged in a flood of dark and interminable waters. In consequence of the action of the waters on mineral substances, vast deposits of sediment accumulated, which, with the aid of pressure and chemical heat, gradually hardened into rocks, strata upon strata, like solid masonry, and varying in thickness from the fraction of a mile to thirty miles or more. Nature seems to have adopted this method of construction as a prerequisite to the severance of the land from the waters. In effecting this object, the explosive forces, long confined in the earth's interior, are supposed to have burst asunder the walls of their prison-house, suddenly upheaving continents and mountains from the depths of a dismal and shoreless ocean. It was then that the "dry land" made its first appearance, and was baptized in the pure sunlight of heaven. The virgin soil of the earth, when thus exposed to the genial influence of the sun, soon produced vegetal life, and vegetal life animal life,--the one the food of the other. Thus Nature ever provides for her guests in advance of their reception. Yet in her formative processes she "makes haste slowly," though she may sometimes leap to conclusions. Her work never ceases. A million of years is to her as one day, and one day as a million of years. Hence everything has its age, and is lost in the ages. Of this fact we have reliable evidence in the strata of the rocks, and in the limited field of our own observation. There can be no doubt the earth has been many times baptized in fire and water, and its crust broken into fragments and thrown into strange angles and relations. These grand upheavals have occurred at dates vastly remote from each other, and are recognized by science as great geological periods. The Ages of Nature, so far as relates to the earth, may be classed briefly as: the primary, or reign of fishes; the secondary, or reign of reptiles; the tertiary, or reign of mammals; and the modern, or reign of man. Each of these ages constitutes a grand chapter in the earth's history, which is easily read and understood by the masters of geological science. The same agencies which were employed in constructing the earth's crust are still employed in reconstructing it. In fact, the work of creation is still going on as in the beginning, if beginning there ever was in Nature's material processes. We see this illustrated in the changes which are produced on the earth's surface in our own time by the action of the rain, the wind, the frost, the flood, the glacier, the volcano, and the earthquake.