These eruptions of granitic or metallic matter--these vast discharges of mineral waters through the fractured surface--would be of frequent occurrence during the primitive epoch we are contemplating. It should not, therefore, be a matter for surprise to find the more ancient rocks almost always fractured, reduced in dimensions by faults and contortions, and often traversed by veins containing metals or their oxides, such as the oxides of copper and tin; or their sulphides, such as those of lead, of antimony, or of iron--which are now the object of the miner’s art. PRIMARY EPOCH. After the terrible tempests of the primitive period--after these great disturbances of the mineral kingdom--Nature would seem to have gathered herself together, in sublime silence, in order to proceed to the grand mystery of the creation of living beings. During the primitive epoch the temperature of the earth was too high to admit the appearance of life on its surface. The darkness of thickest night shrouded this cradle of the world; the atmosphere probably was so charged with vapours of various kinds, that the sun’s rays were powerless to pierce its opacity. Upon this heated surface, and in this perpetual night, organic life could not manifest itself. No plant, no animal, then, could exist upon the silent earth. In the seas of this epoch, therefore, only unfossiliferous strata were deposited. Nevertheless, our planet continued to be subjected to a gradual refrigeration on the one hand, and, on the other, continuous rains were purifying its atmosphere. From this time, then, the sun’s rays, being less obscured, could reach its surface, and, under their beneficent influence, life was not slow in disclosing itself. “Without light,” said the illustrious Lavoisier, “Nature was without life; it was dead and inanimate. A benevolent God, in bestowing light, has spread on the surface of the earth organisation, sentiment, and thought.” We begin, accordingly, to see upon the earth--the temperature of which was nearly that of our equatorial zone--a few plants and a few animals make their appearance. These first generations of life will be replaced by others of a higher organisation, until at the last stage of the creation, man, endowed with the supreme attribute which we call intelligence, will appear upon the earth. “The word _progress_, which we think peculiar to humanity, and even to modern times,” said Albert Gaudry, in a lecture on the animals of the ancient world, delivered in 1863, “was pronounced by the Deity on the day when he created the first living organism.”