The researches of the last ten or fifteen years, in England, have brought to light the skeletons of animals, approaching the _lizard genus_, from _sixty to seventy feet long_!! They are abundant in England, and occasionally found on the continent. Who can say, but that the other genera of animals then existing, were also as much more vast, and misshapen than their present existing types? A single glance at the _geological reminiscences_ of this ancient period must convince any observer, that the vegetable, and specially the animal genera then existing were really astonishing both in _size_, _shape_, and _nature_. It becomes a question of some interest, whether these huge animals ceased to exist, having found their graves in this secondary class of rocks, before the existence of man? There are many reasons which induce a supposition they did cease to exist. Man could scarcely have been safe in the land of these wonderful creatures. Moreover, it is probable their constitutions were adapted to the condition of the world at this period, which we suppose to have been more gross in its air, and water, and more ardent in its climate; as it had not yet settled, and dried; and the waters had not yet sufficiently subsided, to render the earth the abode of the more delicate land-animals, birds, and specially man. It is probable the earth was marshy, with numerous inland lakes, to a considerable extent; the waters still somewhat turbid; the air gross and moist; and the temperature still very high. Such a state of the planet would suit the constitutions of such monsters as the _ichthyosaurus_, and _plesiosaurus_, which would perish as the condition of the globe became more pure, and its temperature reduced. _Tertiary Rocks._ 1. _These rocks were deposited as the earth was actually, and finally redeemed from water, and became fit for the abode of the more delicate and gentle land-animals and birds._ Hence, it is very rare, if ever, the fossil remains of animals which live wholly on land, are found below this class of rocks. But man’s companion animals are found, as elephants, deer, horse, sheep, &c. 2. This class is not so extensively spread as the preceding classes. It includes the _diluvial_ and _alluvial_ formations, and indicate an alternation of fresh and sea waters in its deposition. This class covers the low countries as they slope from primitive districts towards the sea. Such grand vallies are called _diluvial_, because deposited chiefly by the great primitive ocean, as it retired through its last stages to its resting beds. The deposites at the mouths of rivers, or any other deposites from causes now in operation, are called _alluvial_.