When we look back to the earliest of the fossiliferous rocks we can discover something in the nature of their materials themselves which would cause the destruction of their organic tribes. The Silurian strata have been violently disturbed, and much molten matter, during the period of their deposition, injected among them; and by causes such as these, life would suffer greatly, and whole races be suddenly destroyed. Even the strong incased ganoids and placoids of the Devonian period could not always be able to subsist and bear up against the spasmodic throes that produced the conglomerates. Animals preyed likewise upon each other, and by this means kept up then, as now, the general average and balance of life. But in none of these modes can anything like a LAW be inferred, any stated provision be detected, for the outgoing and the incoming of the different genera and species which successively peopled the globe. The rocks differ, as the organisms differ, age to age, from each other: but the series of changes traced in the one class of phenomena, furnish only a few data by which to determine as to the alterations that would be produced in the class cotemporaneous. No land animals have been found in any of the formations beneath the new red sandstone. No quadrupeds existed before the tertiary age. And the monster lizards which so exuberantly sprang into existence during the middle secondary epoch, had all disappeared when these terrestrials occupied the stage. Wisdom we can trace in all the arrangements; care and goodness are everywhere apparent. The seas swarmed with marine animals, while the terrestrials could scarcely have subsisted on an upheaving earth and new forming land. Quadrupeds roamed not over fields so diversified by the lakes and slimy lagoons in which the Saurians found their convenient habitation. And beyond the simple fact, that Divine will so ordained that such things should be, both in the animal and mineral changes in the history of our planet, we have only a ray of light to guide us in interpreting the revolutions and destructions which are therein so indelibly recorded.