rocks, hardly more than 300 in all, forms a singular contrast to the rich assemblages which have been recovered from the

FIG. 159.-Permian Plants; (a) Callipteris conferta (1); (b) Walchia piniformis ().

older systems. But that the land of these times was still richly clothed with vegetation and the sea abundantly stocked with animal life, there can be no doubt. The flora appears to have closely resembled that of the Carboniferous period, a considerable proportion of the species of plants being survivals from the Carboniferous jungles and forests. The Lepidodendra, Sigillariæ, and Calamites, which had been such conspicuous members of all the Palæozoic floras, now appear in diminishing number and variety, and finally die out. With their cessation, new features arise in the vegetation. Among these may be mentioned the abundance of treeferns, which, though they sparingly existed even as far back as Devonian times, now attained a conspicuous development (Psaronius, Caulopteris). The genus of ferns called Callipteris likewise played a prominent part in the Permian woodlands (Fig. 159, a). But perhaps the most remarkable

FIG. 160.-Permian Brachiopods; (a) Productus horridus (reduced); (b) Strophalosia Goldfussi; (c) Camarophoria humbletonensis (3).

feature in the flora was the abundance of its conifers, and the appearance of the earliest forms of cycads. The yewlike conifer Walchia (Fig. 159, b), if we may judge from the abundance of its remains, flourished in great profusion on the drier grounds, mingled with others that bore cones (Ullmannia). The cycads, which now made their advent, continued during Mesozoic time to give the leading character to the vegetation of the globe.

The scanty relics of the Permian fauna, as above stated, have been almost wholly preserved in those strata which were

FIG. 161.-Permian Lamellibranchs; (a) Bakevellia tumida (natural size); (b) Schizodus Schlotheimi (natural size).

deposited during temporary irruptions of the open sea into the inland salt-basins of the time. Some of the Carboniferous genera of brachiopods still survived-Productus, Spirifera, and Strophalosia being conspicuous (Fig. 160). Among the lamellibranchs Axinus, Bakevellia, and Schizodus are frequent forms (Fig. 161). Among the higher molluscs, which

FIG. 162.-Permian Ganoid Fish (Platysomus striatus, 1⁄2).

have been but sparingly preserved in the rocks, the old types of Orthoceras, Cyrtoceras, and Nautilus are still to be noticed. In Europe, the fishes of the time have been chiefly sealed up in the marl-slate or copper-shale (Kupferschiefer); two of the most frequent genera being Palæoniscus and Platysomus (Fig. 162).

Labyrinthodonts continued to abound in the waters. Some of the Carboniferous genera still survived, but with these were associated many new forms, most of which have been discovered in the strata overlying the true Coal

FIG. 163.-Permian Labyrinthodont (Branchiosaurus salamandroides, natural size).

measures of Bohemia (Fig. 163). But a great onward step in the advance of animal organisation was made in Permian time by the appearance of the earliest known lizard-Protorosaurus, which, like the living crocodile, had its teeth implanted in distinct sockets.

In Britain the Permian strata rest unconformably on the Carboniferous system, which must have been greatly disturbed and enormously denuded before they were deposited. They consist of the following subdivisions :

Upper red sandstones, clays, and gypsum (50 to 100 feet thick in the east of England, but swelling out west of the Pennine Chain to 600 feet).

Magnesian limestone-a mass of dolomite ranging up to 600 feet in thickness, and the chief repository of the Permian fossils; remarkable for the curious concretionary forms assumed by many of its beds on the coast of Durham (Fig. 75). Marl-slate-a hard brown shale with occasional limestone bands. Lower red and variegated sandstones with conglomerates and breccias. This division attains a thickness of 3000 feet in Cumberland, but is hardly represented in the east of England.

In Germany, where the Dyas or twofold development of the Permian rocks is so well displayed, the lower subdivision, called Rothliegende, consists of great masses of conglomerate with sandstones, shales, thin limestones, and important intercalations of contemporaneous volcanic rocks, both lavas and tuffs. The upper section is composed chiefly of limestone called Zechstein, and answering to the Magnesian limestone of England. With it are associated beds of anhydrite, gypsum, rock-salt, and bituminous limestone, and underneath it lies the celebrated Kupferschiefer or copper-shale-a black bituminous shale, about 2 feet thick, which has long been extensively worked on the flanks of the Harz Mountains for the ores of copper with which it is impregnated, and which is the great repository for the fossil fishes of the Permian period. This remarkable band of rock was probably deposited in one of the inland basins, which at first may have maintained a free communication with the open sea. But eventually mineral springs, not improbably connected with the volcanic action of the time, brought up such an abundant supply of dissolved metallic salts as to kill the fish and render the water unsuitable for their existence. The metallic salts were reduced and precipitated as sulphides round the organisms, and impregnated the surrounding mud. In the overlying succession of strata, we see how the area was once more overspread by the clearer and opener water, which brought in the fauna of the Zechstein, and then how the basin gradually came to be shut off