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CHAPTER VI.

THE SAURIAN REPTILES.

THE earlier Geologians classified the various rock formations of the earth's crust into primary or first-formed; secondary, second-formed; and tertiary, third-formed rocks. Though a somewhat different meaning is now attached to these terms, they are nevertheless retained as convenient designations. But when referring to life systems they use different terms. Paleozoic, meaning ancient life; Mesozoic, middle life; and Cainozoic, recent life. Taking, then, this course, we find that the fifth day of Genesis opens with the formation of the secondary rocks of Geology, which rocks include the New Red Sandstone, Oolite, and Chalk series; or classifying them according to life periods, this system corresponds with the Mesozoic, or middle life group. Hence the New Red Sandstone has been divided into two parts, one called the Permian, because that kind of rock is typically developed in the province of Perm, in Russia; the other is called the Trias, or triple group, because it appears in Germany in a three-fold aspect, viz. sandstone, limestone, and marl. The reason for this arrangement is, that the fossils of the Permian

rocks are more allied to the coal measure beneath, than to the sandstone and marl above; presenting a paleozoic aspect, while the Triassic fossils have a mesozoic resemblance. So that the secondary rocks now include the Triassic, Oolite, and Cretaceous series. All of them occupying a middle place in Geological history less obscure than the Primary formations. Hence there is less difficulty in deciphering their botanical and zoological character.

Though the rocks differ much in their mineral composition and animal life, still there is sufficient to justify us in regarding them as one great group. We now close the long record of ancient and paleozoic life, during which whole families and races were extinct, being succeeded by other and higher forms of life. And yet there was no break, nor discontinuity in the great change of animal life. One system runs imperceptibly into the other. Furthermore, seeing the vegetation that adorned the earth during this the Mesozoic period bears a near resemblance to ferns, palms, and tropical pines of our own era, the botanist can classify them and institute comparisons with some prospect of success. The Zoologist now meets with all the great divisions of vertebrate life, namely, fishes, reptiles, birds, and some few mammals. The earliest rocks of this period are, as before stated, the Triassic, consisting of reddish coloured sandstone, shelly limestone, and saltyielding marls. The Oolitic consists of calcareous beds, the greater part of which are composed of a conglomerate, or of a collection of small round grains, resembling a cluster of small eggs. Hence, the word Oolite is from two Greek words, 'oon, an egg, and lithos, a stone. These rock formations are traced through England, from Dorsetshire,

by the way of Somersetshire, Gloucestershire, Worcestershire, Northamptonshire, Leicestershire, Rutland, and Lincolnshire, through Yorkshire up to the North of England. And while those rocks were forming, these countries were then covered by the ocean, in which lived countless multitudes of fishes, varying from one inch to several yards in length. Geologians tell us that the new arrangement of sea and land was accompanied by no gigantic rivers, or broad lakes; that the plains were riverless, and the uplands mostly thirsty. Cold-blooded, air-breathing animals became more numerous, while warm-blooded races, such as birds and marsupials, now, for the first time, made their appearance. For now, imbedded in the rocks of this period, are found the foot-tracks of gigantic birds, with the teeth and jaws of small insectivorous mammals. Then worms must have tracked and burrowed in the open sands; shell-fish and crustacea must have crawled and pattered on the muddy beaches of these ancient seas. While reptiles and birds footed the tidal silt of these Oolitic bays and oceans; and when sufficiently consistent and exposed to the drying effects of the sun during a long tidal ebb, the impressions made in the sands would be retained by being hardened, and would then act as a mould for the reception of the next influx of mud. This mould and its cast were then preserved by being covered over with sediment. Hence, it is concluded that during this period numerous birds and reptiles waded and wandered along the shores. Here whirling in sport, there fleeing in fear, and yonder lying in wait, or stealing silently on their devoted victims. During the Oolitic era the geographical conditions of the earth appear to be extremely different from the Triassic

epoch; apparently more favourable to the existence of animal life.

Now the seas show broader, and have southerly expanses. They were more connected and less liable to sudden variation, either in their depth or configuration. The waters were now more regular in their composition, being nearly rid of those super-saline and ferruginous constituents, which in the Trias appear to have been very unfavourable to the growth and preservation of animal life. Towards the middle of this period, we are told, the land assumed a more continuous aspect, and being under a more genial climate, its vast plains, broad rivers and lakes, would prove conducive to animal life. Paleopic forms that lingered in the Triassic era entirely disappeared during the middle portion of the Oolite rocks. It is true that zoophytes and other lowly orders of animals lived during the formation of the Oolitic rocks, but they were near akin to existing races. Three new orders of the Molluscan type were now brought into existence, namely, the Ammonite, Belemnite, and Terebraluta. In general outline the ammonite resembled the nautilus. Looking at the chambers of the shells, we find some were living rooms, and others were, in fact, drawing rooms, in which perhaps the aristocratic ammonite lived. Running round these latter apartments was an hydraulic instrument, or air-tube, by which the animal could alter its specific gravity for purposes of sinking or swimming. These fossils were once supposed to be petrified snakes. There is a legend that St. Hilda, who lived near Whitby, in Yorkshire, was very much annoyed by these reptiles, seeing she kept an establishment for young ladies, so that

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after praying their heads off, she prayed them into stone. The shell of the belemnite is long and conical; the animal lived in the larger end. It was furnished with an ink-bag, for the purpose of muddying the water when it was attacked or pursued. The most remarkable crustacean of this period was the king-crab. The outer portion of its body was covered with a broad horse-shoe shaped buckler, the upper surface of which contained a pair of compound eyes. On the lower surface of the shield was placed the mouth, surrounded by six pairs of legs; the bases are said to have been spinous, or thorny, while the terminations were formed into nipping claws. The first pair was placed in front of the mouth, and mastication was thereby produced. Behind the head comes a second shield composed of six amalgamated segments. In the lower margin of the abdominal shield there was a long sword-like tail, or spine. These curious creatures seem to have commenced life in the upper Silurian rocks, and are now represented by the Limulus. Does it not seem strange that the Trilobite should die out during the coal formation, and these creatures should live on till now; when it is known that they began life together, were of similar habits, and lived in the same sea waters? But it is to the reptilian race that we must give special attention. The fossil remains peculiar to this period prove beyond doubt that there were three classes of reptilian life-the aquatic, the terrestrial, and the aerial; thus corresponding with those mentioned in Genesis i. 20. The translation given by Dr. M'Causland will be found to be critically correct: "And God said, Let the waters swarm forth the reptile that hath the breath of life; and let fowl fly over the earth upon the face