If we allow half a solid foot to the skeleton and other slowly destructible parts of each animal, the remains of these herds would form a cubical mass measuring not much short of four hundred and fifty feet to the side, or a pyramid equal in dimensions to that of Cheops, and as the average life of these animals does not exceed six or seven years, the accumulations of their bones, horns, hoofs, and other durable remains would amount to at least fifteen times as great a volume in a single century. It is true that the actual mass of solid matter, left by the decay of dead domestic quadrupeds and permanently added to the crust of the earth, is not so great as this calculation makes it. The greatest proportion of the soft parts of domestic animals, and even of the bones, is soon decomposed, through direct consumption by man and other carnivora, industrial use, and employment as manure, and enters into new combinations in which its animal origin is scarcely traceable; there is, nevertheless, a large annual residuum, which, like decayed vegetable matter, becomes a part of the superficial mould; and in any event, brute life immensely changes the form and character of the superficial strata, if it does not sensibly augment the quantity of the matter composing them. The remains of man, too, add to the earthy coating that covers the face of the globe. The human bodies deposited in the catacombs during the long, long ages of Egyptian history, would perhaps build as large a pile as one generation of the quadrupeds of the United States. In the barbarous days of old Moslem warfare, the conquerors erected large pyramids of human skulls. The soil of cemeteries in the great cities of Europe has sometimes been raised several feet by the deposit of the dead during a few generations. In the East, Turks and Christians alike bury bodies but a cople of feet beneath the sculptures of the ignoble poor, and of those whose monuments time or accident has removed, are opened again and again to receive fresh occupants. Hence the ground in Oriental cemeteries is pervaded with relics of humanity, of not wholly composed of them; and an examination of the soil of the lower part of the Petit Champ des Morts, at Pera, by the naked eye alone, shows the observer that it consists almost exclusively of the comminuted bones of his fellow-man.] But the vegetable products found with them, and, in rare cases, in the stomachs of some of them, are those of yet extant plants; and besides this evidence, the discovery of works of human art, deposited in juxtaposition with fossil bones, and evidently at the same time and by the same agency which buried these latter--not to speak of human bones found in the same strata--proves that the animals whose former existence they testify were contemporaneous with man, and possibly even extirpated by him. [Footnote: The bones of mammoths and mastodons, in many instances, appear to have been grazed or cut by flint