CLOSE OF THE FIRST EPOCH. 309 in the lapse of ages other strata enveloped them, and preserved the forms of their delicate leaves, and the markings of their trunks and stems, for the inspection of long succeeding ages. But all this time the sea was alive with its multitudes of corals, of echini, trilobites, and peculiar cephalopods, and fishes. It was during this epoch, that the ganoid fishes were most highly developed, and innumerable sharks of all sizes abounded in the carboniferous seas. We have now arrived at the end of our first epoch, just before the introduction of reptiles. There seems in some respects to have been a progression in organization, and yet, not such as to support the view, however plausible, of the agency of an inferior type of organization in introducing a higher group. The corals and the encrinites still remained with but little change, but the trilobites were nearly extinct, the cephalapodous animals, retaining till now the straight and elongated form of the orthceratites, assumed the spiral form of the goniatite. The small fishes of the early epochs gave place to large and voracious species, powerful swimmers and insatiably voracious; vast tracts of country were settling down, and the rich and rank vegetation, which covered the land at the time of the coal epoch, was prepared for the first stage of its change into coal. During all this period, we must not fail to note the entire absence of all the grasses, which now form so prominent a portion of existing plants; indeed, the whole face of the globe, was so entirely different from its present appearance, that could we now behold it, we might realize that we were looking upon another planet. It is not for us to discuss the question of the length of time necessary to accomplish all those changes which the globe has passed through, or to speculate upon the distinct efforts of creative power exhibited throughout those countless ages. It is sufficient for us to know that myriads of beings, dissimilar to any now existing, or only remotely connected, flourished perhaps for thousands of years,. when suddenly they disappeared, and quite as suddenly new forms replaced those lost. There can be no way of accounting for these changes in the forms of animal and vegetable life, except by the direct interposition of a creative power. N* CHAPTER XIV. The second Epoch. "And later yet the sea o'erspread And this was once an ocean's bed, Anon. We THE epoch now to be considered, is in many respects the most interesting, as it is certainly the most abundant in its fossil remains. In our present volume we can only glance at the charteristic features, leaving wholly untouched those minor details, which often make the most interesting part of a history. can therefore only hope that the reader will make a beginning here, but search elsewhere for more extended and minute information. Immediately above the coal measures, lies a coarse sandy deposit, which appears to be the ruins of some more ancient rock, consolidated by pressure and the infiltration of water impregnated with iron. The shores of the previously existing lands, seem to have gradually been depressed, forming vast beds of coal; upon these, the beds of sand and marl were loosely and rapidly deposited, and are not exceedingly rich in their fossil remains. There is however, one interesting and remarkable fact connected with these deposits, and that is, distinct tracks of reptiles and birds; to these we shall allude again presently. The lowest member of the new red sandstone group is the magnesian limestone, so called from having a considerable portion of carbonate of magnesia mixed with its carbonate of lime; it is a stone exceedingly valuable for building purposes. This limestone contains a few fossils, corals and shells, and occasionally a few fragments or whole skeletons of fishes. The fishes are all remarkable for a peculiar structure of tail characteristic also of the fishes of the older strata, this structure is called by M. Agassiz the hete rocercal, the tail being unequally lobed as in fig. 1, which is the tail of the shark, and the vertebral column running along, the upper lobe. On the other hand, in nearly all the living species, the tail is homocercal as in fig. 2, which is the tail of a herring, the vertebral column not extending to the upper lobe. We have remarked that the first tracks of reptiles are met with in this system of deposits. Below we represent the appearance of these footprints as observed in England and Germany. It will be perceived that there are two impressions which always accompany each other, and they are not unlike the human hand, hence the animal was named cheirotherium or hand beast. This animal was for a long time supposed to be allied to the kangaroo, and like it a marsupial, i. e. having a pouch in which to carry its young; but more recently Prof. Owen, from a careful examination of teeth and other bones found in the new red sandstone, has determined it to belong to the class of batrachians, or frogs, toads, salamanders, &c., and from the peculiar structure of its teeth, he has given to this genus the name labyrinthodon, or labyrinth tooth. Besides the tracks just described, are found those of turtles, of a little lizard with a bird-like beak, and the trails of molluscs, and vermes, and the ripple marks of the ancient seas. By far the most remarkable tracks occurring in the new red sandstone group, are those of gigantic birds, the foot-prints being seventeen inches long, and the stride of the bird from four to six feet. It is somewhat remarkable that nearly all the fossil foot marks yet discovered, occur upon some member of the new red sandstone group. On the same stone are impressions of rain drops. "It is a most interesting thought," observes Prof. Hitchcock," that while millions of men who have striven hard to transmit some trace of their existence to future generations, have sunk into utter oblivion, the simple footsteps of animals, that existed thousands, nay, tens of thousands of years ago, should remain as fresh and distinct as if yesterday impressed; even though nearly every other vestige of their existence has vanished. Nay still more strange is it, that even the pattering of a shower at that distant period, should have left marks equally distinct, and registered with infallible certainty the direction of the wind." When these foot prints were first discovered their enormous size seemed an insuperable objection to the opinion that they were bird tracks. But recently in the island of New Zealand, the bones of an immense wingless bird have been found to which the name Dinornis, or terrible bird, has been given. Below is an outline representing the size of this extraordinary animal compared with a man. Immediately above the new red sandstone in some parts of the . world, but particularly in England, is deposited a fine sandy and marly stratum, consisting of distinct layers with occasional limestones, and exceedingly abundant in remarkable fossil remains. To this the name Lias has been given, and the reptilian remains imbedded in it are the most magnificent objects of the Creator's hand. During the deposit of these muddy beds which were unfavorable to the growth of corals, we find but few traces of these animals, but on the contrary the crinoidea, already alluded to, were developed in singular and beautiful forms, and also very peculiar forms of the cephalapodic group. Among the marine reptiles of the epoch we are now considering, two are particularly noticeable. The Plesiosaurus, or almost lizard, and the Ichthyosaurus, or fish lizard. Below we represent the plesiosarus, which possesses a head small, and lizard-like, with teeth like a croco dile, a neck of enormous length like the body of a serpent, and a back and tail having the proportions of an ordinary quadruped. It is furnished with four paddles, and is supposed to have inhabited the shallow waters; darting by means of its long neck, suddenly at the fish which came near it. The largest complete specimen of the plesiosarus yet discovered is about eighteen feet in length. Fierce and voracious as this animal undoubtedly was, yet it had an enemy in the ichthyosarus represented in the following wood cut. This formidable marine reptile sometimes attain ed to a length or thirty or forty feet, and like the whale possessed a smooth and naked skin. The eyes were enormously large and provided with bony plates, or divisions arranged around the pupil. There are instances where the diameter of the orbit is eighteen |