importance. The sandstones are quarried in many districts for building purposes, as are also some of the magnesian limestones (Durham and Yorkshire), which dress well, and are often exceedingly durable. The limestones are likewise used in agriculture, as mortar for the builder, and for the extraction of magnesia; while certain of the compact varieties found in Germany furnish blocks for lithographic printing. Gypsum is an abundant product of some of the marls; while in Germany the kupfer-schiefer has been long mined as an ore of copper, and furnishes a large proportion of that valuable metal. RECAPITULATION. The system above described consists essentially of reddish sandstones, yellowish magnesian limestones, and slaty calcareous beds. From the prevailing hues of its strata, and from the fact of its lying immediately above the coal-measures, it has been termed the new red sandstone, in contradistinction to the old red, which lies beneath. Along with the saliferous marls and variegated sandstones of the triassic strata above, it was early observed to hold a sort of middle place among the secondary formations; hence the lias, oolite, and chalk were considered as younger or upper secondaries, while the new red, the carboniferous strata, and the old red, were termed the older or lower secondaries. From the fact of the lower members of the new red sandstone containing fossils more or less allied to carboniferous types, and its upper members imbedding those less or more allied to oolitic forms, it has been separated into two distinct systems—the Permian (from Perm in Russia, where the lower beds are extensively developed) and the Triassic, regarding the triple group of Germany as typical of the upper strata. Adopting this view, we have the following synopsis : TRIAS. PERMIAN. Keuper. Lower bunter. Kupfer-schiefer. Rothe-liegende. Saliferous marls and girts. Variegated sandstone. Gypseous marls and grits. Red sandstones. In the Permian the fossils are plants akin to those of the coalmeasures, with crinoids, shell-fish, fishes with heterocercal tails, and frog-like reptiles. In the Trias, as will be seen in the next chapter, the plants resemble oolitic types, and the animal remains are corals, encrinites, shell-fish, fishes with homocercal tails, amphibious reptiles, traces of birds, and small marsupial mammals. Taking the whole composition, succession, and remains of both systems, they indicate a period of shallow seas supercharged with saline matter, of muddy estuaries and lagoons, of an arid and warm climate, and of frequent submergences and upheavals. During the period many forms of life disappeared, and were succeeded by others of a different type and order; hence the Permian group is regarded as paleozoic, and the Triassic as mesozoic. On the whole, the Permian strata have been little disturbed by igneous rocks, and new red sandstone districts are in consequence rather flat and monotonous. The soil is of medium quality, and affords rich verdant pastures rather than arable land for mixed husbandry. Industrially, the system yields building-stone, limestone, gypsum, copper, and occasionally valuable seams of coal, if we adopt the belief of American geologists, that the red and grey sandstones of Virginia and North Carolina are of Permian epoch. XII. THE TRIASSIC SYSTEM, COMPRISING THE KEUPER, MUSCHELKALK, AND BUNTER SANDSTEIN OF GERMANY, OR UPPER NEW RED SANDSTONE OF ENGLAND. 109. THE reasons for separating what was formerly known as the "New Red Sandstone" into two distinct systems-the Permian and Triassic-have been stated in the preceding chapter. Before this division, it was usual to arrange the new red sandstone, as developed in England, into upper, middle, and lower groups— the upper comprising the saliferous marls and variegated sandstones of Cheshire; the middle, the magnesian limestones of York and Durham; and the lower, those reddish sandstones and grits which immediately overlie the coal-measures in the north of England. The succession of the strata composing the lower and middle groups has been tabulated in paragraph 104. The following exhibits the lithology of the upper section :— VARIEGATED MARLS.-Red, with bluish, greenish, and whitish laminated clays or marls holding gypsum generally, and rock-salt partially (as in Cheshire). Interstratified with these marls are certain grey and whitish sandstones. VARIEGATED SANDSTONES.-Red sandstones, with white and mottled portions; the lower strata in some districts pebbly. In addition to these marls and sandstones, there is developed on the Continent a considerable thickness of shelly fossiliferous limestone known as the MUSCHELKALK; and when this is interpolated, the upper new red consists of three well-marked members; hence the Trias, or triple system of German geologists. Tabulated in descending order, the following exhibits the details of the system as developed in Germany and England :— 1. KEUPER. Germany. Saliferous and gypseous England. Saliferous and gypseous marls, with grey and whitish sandstones. For the purposes of the beginner, it is enough, perhaps, to remember that the Triassic system consists essentially of three groups-1, Keuper marls and grits (saliferous marls); 2, Muschelkalk (shelly limestone); and, 3, Bunter Sandstein (variegated sandstones). 110. When we turn to the fossils of the system we find the Plants of the Coal and Permian epochs represented only by a few calamites, equisetums, and ferns, and their place taken by others apparently allied to the palms, cycads, zamias, and true pines. We have now few corals; but star-fish (aspidura) and crinoids (encrinus liliiformis) occur abundantly in the German muschelkalk. Of shell-fish, terebratula and spirifer still occur; but the great flush of brachiopods (productus, &c.) which marked the period of the carboniferous limestone is unknown. Of triassic bivalves the avicula, mya, plagiostoma, and ostrea, are perhaps the most abundant ; and of chambered shells the ceratites, allied to the ammonite, is the most common genus. Crustaceans of minute forms, estheria (posidonia), are abundant in the fine-grained lime 18!! 1, Encrinus liliiformis; 2, Myophoria lineata; 3, Ceratites nodosus; 4, Estheria minuta; 5, Plagiostoma obliqua; 6, Pemphix Sueurii. stones; craw-fish like forms (pemphix) also occur; and beetle-like insects are by no means uncommon in the same beds. Of sauroid fishes numerous species have been discovered, as the saurichthys (sauroid-fish), gyrolepis (twisted scale), acrodus (pointed-tooth), and others, all deriving their names from some marked peculiarity in appearance. Of reptiles several curious genera have been found, allied to the lizards and monitors of our own time, the most characteristic being the labyrinthodon (so named from Restored outline of Labyrinthodon pachygnathus.-OwEN. the structure of its teeth), the phytosaurus (plant-saurian), the nothosaurus or doubtful saurian, the rhynchosaurus (beaked saurian), the small lizard-like telerpeton of the Lossiemouth sandstones, and the large crocodilian-like staganolepis of the same formation-if that formation shall eventually be proved to be of Triassic age (see par 85). To these may be added the curious |
