spirifer and productus, are in deep water; huge nautiluslike cephalopods, nautilus, goniatite, and orthoceratite, in 1, Dithyrocaris; 2, Limuloides (Bellinurus); 3, Cypris-magnified; 4, Spirorbis the open sea; gasteropods, like euomphalus and pleurotomaria, on shore; acephalans, like unio and anodon, in freshwater and tidal estuaries; and others, like aviculopecten, mytilus, and mactra, in its shallower bays. The boneencased fishes of the old red sandstone have now disappeared, and their place is taken by the more fish-like forms (if we may so express it) of megalichthys, palæoniscus, amblypterus, eurynotus, and platysomus; by gigantic shark-like cestracionts, whose teeth (helodus, poecilodus, psammodus, &c.) and fin-spines (gyracanthus, ctenacanthus, oracanthus, &c.) are alone preserved to us; and huge sauroid genera (rhizodus, &c.), whose dentition marks an affinity to the higher class of reptiles. In many localities these fishes seemed to have swarmed in shoals, preying on shell-fish and 1, Terebratula; 2, Productus; 3, Spirifera; 4, Aviculopecten; 5, Bellerophon; 6. Loxonema; 7, Murchisonia; 8, Pleurotomaria; 9, Euomphalus; 10, Conularia; 11, Goniatites; 12, Orthoceratite. young coral-growth, and also on one another, as is amply testified by their fossil droppings or coprolites, which crowd the shales or muds of the carboniferous sea-bed. In reptilian life, the forms are, on the whole, of lowly organisation, indicating, as it were, the recent advent of the order,—an order whose remains have not been discovered with certainty in any preceding formation. From the European and Nova Scotian coal-fields, however, we have five or six genera of frog-like and lizard-like forms-some evidently aquatic, others amphibious, and some fitted for an arboreal habitat. They are known by such names as archæogosaurus (ancient land-lizard), parabatrachus (frog-like reptile), and dendrerpeton (tree-lizard), and carry the imagination back to stagnant pools, to sludgy river-shores, and to ancient forestgrowths, whose hollow trunks furnished at once their insectfood and a place of security and shelter. In these early reptiles in the persistence of their dorsal chord, their gillarches, their large median and lateral throat-plates, and other piscine characters-Professor Owen traces a "linking and blending" of the two cold-blooded vertebrate groups; archæogosaurus conducting, as it were, the march of life. from the fish proper to these labyrinthodont reptiles that come boldly into force in the Permian and triassic eras. Fin Spines: 1, Pleuracanthus; 2, Gyracanthus ; 3, Ctenacanthus. Palatal Teeth: 4, Ctenoptychius; 5, Psammodus; 6, Poecilodus. 7, Jaw of Rhizodus, showing Reptilian Teeth. The course of vitality is thus for ever onward and upward -onward in the introduction of forms having more varied geographical adaptations, and upward in the manifestation. of higher physiological and functional performance. Such is the panorama of carboniferous life-an unparalleled exuberance of endogenous flora; a wonderful profusion of estuarine and marine life in all its aspects: but as yet few insects, none of the higher reptiles, no birds, no mammals! And yet, looking at mere external conditions, it is difficult to conceive how, in some of their specific forms, they should not be there. There was abundant food for insects-why not insectivorous reptiles and mammals to prey upon them? Besides insects, there were also fruits and seeds-why not birds to feed upon them; and why not the larger herbivorous reptiles and quadrupeds to browse upon the excess of vegetation that then clothed so large a portion of the earth's surface? True, such plants as equisetums, club-mosses, ferns, and coniferous trees, are, from the peculiar principles they contain, the least fitted for the sustenance of known animals; but then there were the succulent shoots and roots of palms, of calamites, poacites, and other leafy herbage-the fruits of palms and other allied trees, and these we know are the favourite food of many mammals at the present day. Nay more; as we know that certain savage tribes exist on palm fruits, or farinaceous roots, and on the fish of the ocean, we might carry this sort of reasoning still further, and ask whether the human race, in some of its lowlier phases, might not also have been participators in the life of the carboniferous era? To questions such as these the paleontologist has no other answer to offer than that he has hitherto failed to detect the remains of birds and mammals; that as the food to be consumed and the consumer are generally concomitants, so he more than expects the discovery of higher life during the coal-period; but that this higher life, though discovered to-morrow, would necessarily take its stand lower in the scale of organisation than the reptiles, and birds, and mammals which are found in the immediately succeeding formations of the new red sandstone and oolite. If there is one truth that geology has established more clearly than another, it is that of the progressive evolution of life on this globe; not progress from imperfection to perfection, for all are alike fitted. to the end for which they were created, but progress from |