A few Star-fishes and Brittle-stars are known to occur in the Carboniferous rocks; but the only other Echinodemls of this period which need be noticed are the Sea-urchins (Echinoids). Detached plates and spines of these are far from rare in the Carboniferous deposits; but anything like perfect specimens are exceedingly scarce. The Carboniferous Sea-urchins agree with those of the present day in having the body enclosed in a shell formed by an enormous number of calcareous plates articulated together. The shell may be regarded as, typically, nearly spherical in shape, with the mouth in the centre of the base, and the excretory opening or vent at its summit. In both the ancient forms and the recent ones, the plates of the shell are arranged in ten zones which generally radiate from the summit to the centre of the base. In five of these zones—termed the "ambulacral areas"—the plates are perforated by minute apertures or "pores," through which the animal can protrude the little water-tubes ("tube-feet") by which its locomotion is carried on. In the other five zones—the so-called "inter-ambulacral areas"—the plates are of larger size, and are not perforated by any apertures. In all the modern Sea-urchins each of these ten zones, whether perforate or imperforate, is composed of two rows of plates; and there are thus twenty rows of plates in all. In the Palaeozoic Sea-urchins, on the other hand, the "ambulacral areas" are often like those of recent forms, in consisting of two rows of perforated plates (fig. 119); but the "inter-ambulacral areas" are always quite peculiar in consisting each of three, four, five, or more rows of large imperforate plates, whilst there are sometimes four or ten rows of plates in the "ambulacral areas" also: so that there are many more than twenty rows of plates in the entire shell. Some of the Palaeozoic Sea-urchins, also, exhibit a very peculiar singularity of structure which is only known to exist in a very few recently-discovered modern forms (viz., Calveria and Phormosoma). The plates of the inter-ambulacral areas, namely, overlap one another in an imbricating manner, so as to communicate a certain amount of flexibility to the shell; whereas in the ordinary living forms these plates are firmly articulated together by their edges, and the shell forms a rigid immovable box. The Carboniferous Sea-urchins which exhibit this extraordinary peculiarity belong to the genera Lepidechinus and Lepidesthes, and it seems tolerably certain that a similar flexibility of the shell existed to a less degree in the much more abundant genus Archoeocidaris. The Carboniferous Sea-urchins, like the modern ones, possessed movable spines of greater or less length, articulated to the exterior of the shell; and these structures are of very common occurrence in a detached condition. The most abundant genera are Archoeocidaris and Paloechinus; but the characteristic American forms belong principally to Melonites, Oligoporus, and Lepidechinus.



Amongst the Annelides it is only necessary to notice the little spiral tubes of Spirorbis Carbonarius (fig. 120), which are commonly found attached to the leaves or stems of the Coal-plants. This fact shows that though the modern species of Spirorbis are inhabitants of the sea, these old representatives of the genus must have been capable of living in the brackish waters of lagoons and estuaries.



The Crustaceans of the Carboniferous rocks are numerous, and belong partly to structural types with which we are already familiar, and partly to higher groups which come into existence here for the first time. The gigantic Eurypterids of the Upper Silurian and Devonian are but feebly represented, and make their final exit here from the scene of life. Their place, however, is taken by peculiar forms belonging to the allied group of the Xiphosura, represented at the present day by the King-crabs or "Horse-shoe Crabs" (Limulus). Characteristic forms of this group appear in the Coal-measures both of Europe and America; and though constituting three distinct genera (Prestwichia, Belinurus, and Euprooeps), they are all nearly related to one another. The best known of them, perhaps, is the Prestwichia rotundala of Coalbrookdale, here figured (fig. 121). The ancient and formerly powerful order of the Trilobites also undergoes its final extinction here, not surviving the deposition of the Carboniferous Limestone series in Europe, but extending its range in America into the Coal-measures. All the known Carboniferous forms are small in size and degraded in point of structure, and they are referable to but three genera (Phillipsia, Griffithides, and Brachymetopus), belonging to a single family. The Phillipsia seminifera here figured (fig. 122, a) is a characteristic species in the Old World. The Water-fleas (Ostracoaa) are extremely abundant in the Carboniferous rocks, whole strata being often made up of little else than the little bivalved shells of these Crustaceans. Many of them are extremely small, averaging about the size of a millet-seed; but a few forms, such as Entomoconchus Scouleni (fig. 122, c), may attain a length of from one to three quarters of an inch. The old group of the Phyllopods is is likewise still represented in some abundance, partly by tailed forms of a shrimp-like appearance, such as Dithyrocaris (fig. 122, d), and partly by the curious striated Estherioe and their allies, which present a curious resemblance to the true Bivalve Molluscs (fig. 122, b). Lastly, we meet for the first time in the Carboniferous rocks with the remains of the highest of all the groups of Crustaceans—namely, the so-called "Decapods," in which there are five pairs of walking-limbs, and the hinder end of the body ("abdomen") is composed of separate rings, whilst the anterior end is covered by a head-shield or "carapace." All the Carboniferous Decapods hitherto discovered resemble the existing Lobsters, Prawns, and Shrimps (the Macrura), in having a long and well-developed abdomen terminated by an expanded tail-fin. The Paloeocaris typus (fig. 122, e) and the Anthrapaloemon gracilis (fig. 122, f), from the Coal-measures of Illinois, are two of the best understood and most perfectly preserved of the few known representatives of the "Long-tailed" Decapods in the Carboniferous series. The group of the Crabs or "Short-tailed" Decapods (Brachyura), in which the abdomen is short, not terminated by a tail-fin, and tucked away out of sight beneath the body, is at present not known to be represented at all in the Carboniferous deposits.



In addition to the water-inhabiting group of the Crustaceans, we find the articulate animals to be represented by members belonging to the air-breathing classes of the Arachnida, Myriapoda, and Insecta. The remains of these, as might have been expected, are not known to occur in the marine limestones of the Carboniferous series, but are exclusively found in beds associated with the Coal, which have been deposited in lagoons, estuaries, or marshes, in the immediate vicinity of the land, and which actually represent an old land-surface. The Arachnids are at present the oldest known of their class, and are represented both by true Spiders and Scorpions. Remains of the latter (fig. 123) have been found both in the Old and New Worlds, and indicate the existence in the Carboniferous period of Scorpions differing but very little from existing forms. The group of the Myriapoda, including the recent Centipedes and Galley-worms, is likewise represented in the Carboniferous strata, but by forms in many respects very unlike any that are known to exist at the present day. The most interesting of these were obtained by Principal Dawson, along with the bones of Amphibians and the shells of Land-snails, in the sediment filling the hollow trunks of Sigillaria, and they belong to the genera Xylobius (fig. 124) and Archiulus. Lastly, the true insects are represented by various forms of Beetles (Coleoptera), Orthoptera (such as Cockroaches), and Neuropterous insects resembling those which we have seen to have existed towards the close of the Devonian period. One of the most remarkable of the latter is a huge May-fly (Haplophlebium Barnesi, fig. 125), with netted wings attaining an expanse of fully seven inches, and therefore much exceeding any existing Ephemerid in point of size.



The lower groups of the Mollusca are abundantly represented in the marine strata of the Carboniferous series by Polyzoans and Brachiopods. Amongst the former, although a variety of other types are known, the majority still belong to the old group of the "Lace-corals" (Fenestellidoe), some of the characteristic forms of which are here figured (fig. 126). The graceful netted fronds of Fenestella, Retepora, and Polypora (fig. 126, a) are highly characteristic, as are the slender toothed branches of Glauconome (fig. 126, b). A more singular form, however, is the curious Archimedes (fig. 126, c), which is so characteristic of the Carboniferous formation of North America. In this remarkable type, the colony consists of a succession of funnel-shaped fronds, essentially similar to Fenestella in their structure, springing in a continuous spiral from a strong screw-like vertical axis. The outside of the fronds is simply striated; but the branches exhibit on the interior the mouths of the little cells in which the semi-independent beings composing the colony originally lived.



The Brachiopods are extremely abundant, and for the most part belong to types which are exclusively or principally Palaeozoic in their range. The old genera Strophomena, Orthis (fig. 127, c), Athyris (fig. 127, e), Rhynchonella (fig. 127, g), and Spirifera (fig. 127, h), are still well represented—the latter, in particular, existing under numerous specific forms, conspicuous by their abundance and sometimes by their size. Along with these ancient groups, we have representatives—for the first time in any plenty—of the great genus Terebratula (fig. 127, d), which underwent a great expansion during later periods, and still exists at the present day. The most characteristic Carboniferous Brachiopods, however, belong to the family of the Productidoe, of which the principal genus is Producta itself. This family commenced its existence in the Upper Silurian with the genus Chonetes, distinguished by its spinose hinge-margin. This genus lived through the Devonian, and flourished in the Carboniferous (fig. 127, f). The genus Producta itself, represented in the Devonian by the nearly allied Productella, appeared first in the Carboniferous, at any rate, in force, and survived into the Permian; but no member of this extensive family has yet been shown to have over-lived the Palaeozoic period. The Productoe of the Carboniferous are not only exceedingly abundant, but they have in many instances a most extensive geographical range, and some species attain what may fairly be considered-gigantic dimensions. The shell (fig. 127, a and b) is generally more or less semicircular, with a straight hinge-margin, and having its lateral angles produced into larger or smaller ears (hence its generic name—"cochlea producta"). One valve (the ventral) is usually strongly convex, whilst the other (the dorsal) is flat or concave, the surface of both being adorned with radiating ribs, and with hollow tubular spines, often of great length. The valves are not locked together by teeth, and there is no sign in the fully-grown shell of an opening in or between the valves for the emission of a muscular stalk for the attachment of the shell to foreign objects. It is probable, therefore, that the Productoe, unlike the ordinary Lamp-shells, lived an independent existence, their long spines apparently serving to anchor them firmly in the mud or ooze of the sea-bottom; but Mr Robert Etheridge, jun.; has recently shown that in one species the spines were actually employed as organs of adhesion, whereby the shell was permanently attached to some extraneous object, such as the stem of a Crinoid. The two species here figured are interesting for their extraordinarily extensive geographical range—Producta semireticulata (fig. 127, a) being found in the Carboniferous rocks of Britain, the continent of Europe, Central Asia, China, India, Australia, Spitzbergen, and North and South America; whilst P. Longispina (fig. 127, b) has a distribution little if at all less wide.



The higher Mollusca are abundantly represented in the Carboniferous rocks by Bivalves (Lamellibranchs), Univalves (Gasteropoda), Winged-snails (Pteropoda), and Cephalopods. Amongst the Bivalves we may note the great abundance of Scallops (Aviculopecten and other allied forms), together with numerous other types—some of ancient origin, others represented here for the first time. Amongst the Gasteropods, we find the characteristically Palaeozoic genera Macrocheilus and Loxonema, the almost exclusively Palaeozoic Euomphalus, and the persistent, genus Pleurotomaria; whilst the free-swimming Univalves (Heteropoda)are represented by Bellerophon and Porcellia, and the Pteropoda by the old genus Conularia. With regard to the Carboniferous Univalves, it is also of interest to note here the first appearance of true air-breathing or terrestrial Molluscs, as discovered by Dawson and Bradley in the Coal-measures of Nova Scotia and Illinois. Some of these (Conulus priscus) are true Land-snails, resembling the existing Zonites; whilst others (Pupa vetusta, fig. 128) appear to be generically inseparable from the "Chrysalis-shells" (Pupa) of the present day. All the known forms—three in number—are of small size, and appear to have been local in their distribution or in their preservation. More important, however, than any of the preceding, are the Cephalopoda, represented, as before, exclusively by the chambered shells of the Tetrabranchiates. The older and simpler type of these, with simple plain septa, and mostly a central siphuncle, is represented by the straight conical shells of the ancient genus Orthoceras, and the bow-shaped shells of the equally ancient Cyrtoceras—some of the former attaining a great size. The spirally-curved discoidal shells of the persistent genus Nautilus are also not unknown, and some of these likewise exhibit very considerable dimensions. Lastly, the more complex family of the Ammonitidoe, with lobed or angulated septa, and a dorsally-placed siphuncle (situated on the convex side of the curved shells), now for the first time commences to acquire a considerable prominence. The principal representative of this group is the genus Goniatites (fig. 129), which commenced its existence in the Upper Silurian, is well represented in the Devonian, and attains its maximum here. In this genus, the shell is spirally curved, the septa are strongly lobed or angulated, though not elaborately frilled as in the Ammonites, and the siphuncle is dorsal. In addition to Goniatites, the shells of true Ammonites, so characteristic of the Secondary period, have been described by Dr Waagen as occurring in the Carboniferous rocks of India.



Coming finally to the Vertebrata, we have in the first place to very briefly consider the Carboniferous fishes. These are numerous; but, with the exception of the still dubious "Conodonts," belong wholly to the groups of the Ganoids and the Placoids (including under the former head remains which perhaps are truly referable to the group of the Dipnoi or Mud-fishes). Amongst the Ganoids, the singular buckler-headed fishes of the Upper Silurian and Devonian (Cephalaspidoe) have apparently disappeared; and the principal types of the Carboniferous belong to the groups respectively represented at the present day by the Gar pike (Lepidosteus) of the North American lakes, and the Polypterus of the rivers of Africa. Of the former, the genera Paloeoniscus and Amblypterus (fig. 130), with their small rhomboidal and enamelled scales, and their strongly unsymmetrical tails, are perhaps the most abundant. Of the latter, the most important are species belonging to the genera Megalichthys and Rhizodus, comprising large fishes, with rhomboidal scales, unsymmetrical ("heterocercal") tails, and powerful conical teeth. These fishes are sometimes said to be "sauroid," from their presenting some Reptilian features in their organisation, and they must have been the scourges of the Carboniferous seas. The remains of Placoid fishes in the Carboniferous strata are very numerous, but consist wholly of teeth and fin-spines, referable to forms more or less closely allied to our existing Port Jackson Sharks, Dog-fishes, and Rays. The teeth are of very various shapes and sizes,—some with sharp, cutting edges (Petalodus, Cladodus, &c.); others in the form of broad crushing plates, adapted, like the teeth of the existing Port Jackson Shark (Cestracion Philippi), for breaking down the hard shells of Molluscs and Crustaceans. Amongst the many kinds of these latter, the teeth of Psammodus and Cochliodus (fig. 131) may be mentioned as specially characteristic. The fin-spines are mostly similar to those so common in the Devonian deposits, consisting of hollow defensive spines implanted in front of the pectoral or other fins, usually slightly curved, often superficially ribbed or sculptured, and not uncommonly serrated or toothed. The genera Ctenacanthus, Gyracanthus, Homacanthus, &c., have been founded for the reception of these defensive weapons, some of which indicate fishes of great size and predaceous habits.



In the Devonian rocks we meet with no other remains of Vertebrated animals save fishes only; but the Carboniferous deposits have yielded remains of the higher group of the Amphibians. This class, comprising our existing Frogs, Toads, and Newts, stands to some extent in a position midway between the class of the fishes and that of the true reptiles, being distinguished from the latter by the fact that its members invariably possess gills in their early condition, if not throughout life; whilst they are separated from the former by always possessing true lungs when adult, and by the fact that the limbs (when present at all) are never in the form of fins. The Amphibians, therefore, are all water-breathers when young, and have respiratory organs adapted for an aquatic mode of life; whereas, when grown up, they develop lungs, and with these the capacity for breathing air directly. Some of them, like the Frogs and Newts, lose their gills altogether on attaining the adult condition; but others, such as the living Proteus and Menobranchus, retain their gills even after acquiring their lungs, and are thus fitted indifferently for an aquatic or terrestrial existence. The name of "Amphibia," though applied to the whole class, is thus not precisely appropriate except to these last-mentioned forms (Gr. amphi, both; bios, life). The Amphibians also differ amongst themselves according as to whether they keep permanently the long tail which they all possess when young (as do the Newts and Salamanders), or lose this appendage when grown up (as do the Frogs and Toads). Most of them have naked skins, but a few living and many extinct forms have hard structures in the shape of scales developed in the integument. All of them have well-ossified skeletons, though some fossil types are partially deficient in this respect; and all of them which possess limbs at all have these appendages supported by bones essentially similar to those found in the limbs of the higher Vertebrates. All the Carboniferous Amphibians belong to a group which has now wholly passed away—namely, that of the Labyrinthodonts. In the marine strata which form the base of the Carboniferous series these creatures have only been recognised by their curious hand-shaped footprints, similar in character to those which occur in the Triassic rocks, and which will be subsequently spoken of under the name of Cheirotherium. In the Coal-measures of Britain, the continent of Europe, and North America, however, many bones of these animals have been found, and we are now tolerably well acquainted with a considerable number of forms. All of them seem to have belonged to the division of Amphibians in which the long tail of the young is permanently retained; and there is evidence that some of them kept the gills also throughout life. The skull is of the characteristic Amphibian type (fig. 132, a), with two occipital condyles, and having its surface singularly pitted and sculptured; and the vertebrae are hollowed out at both ends. The lower surface of the body was defended by an armour of singular integumentary shields or scales (fig. 132, c); and an extremely characteristic feature (from which the entire group derives its name) is, that the walls of the teeth are deeply folded, so as to give rise to an extraordinary "labyrinthine" pattern when they are cut across (fig. 132, b). Many of the Carboniferous Labyrinthodonts are of no great size, some of them very small, but others attain comparatively gigantic dimensions, though all fall short in this respect of the huge examples of this group which occur in the Trias. One of the largest, and at the same time most characteristic, forms of the Carboniferous series, is the genus Anthracosaurus, the skull of which is here figured.

No remains of true Reptiles, Birds, or Quadrupeds have as yet been certainly detected in the Carboniferous deposits in any part of the world. It should, however, be mentioned, that Professor Marsh, one of the highest authorities on the subject, has described from the Coal-formation of Nova Scotia certain vertebrae which he believes to have belonged to a marine reptile (Eosaurus Acadianus), allied to the great Ichthyosauri of the Lias. Up to this time no confirmation of this determination has been obtained by the discovery of other and more unquestionable remains, and it therefore remains doubtful whether these bones of Eosaurus may not really belong to large Labyrinthodonts.

LITERATURE.

The following list contains some of the more important of the original sources of information to which the student of Carboniferous rocks and fossils may refer:—

(1) 'Geology of Yorkshire,' vol. ii.; 'The Mountain Limestone District.' John Phillips. (2) 'Siluria.' Sir Roderick Murchison. (3) 'Memoirs of the Geological Survey of Great Britain and Ireland.' (4) 'Geological Report on Londonderry,' &c. Portlock. (5) 'Acadian Geology.' Dawson. (6) 'Geology of Iowa,' vol. i. James Hall. (7) 'Reports of the Geological Survey of Illinois' (Geology and Palaeontology). Meek, Worthen, &c. (8) 'Reports of the Geological Survey of Ohio' (Geology and Palaeontology). Newberry, Cope, Meek, Hall, &c. (9) 'Description des Animaux fossiles qui se trouvent dans le Terrain Carbonifere de la Belgique,' 1843; with subsequent monographs on the genera Productus and Chonetes, on Crinoids, on Corals, &c. De Koninck. (10) 'Synopsis of the Carboniferous Fossils of Ireland.' M'Coy. (11) 'British Palaeozoic Fossils.' M'Coy. (12) 'Figures of Characteristic British Fossils.' Baily. (13) 'Catalogue of British Fossils.' Morris. (14) 'Monograph of the Carboniferous Brachiopoda of Britain' (Palaeontographical Society). Davidson. (15) 'Monograph of the British Carboniferous Corals' (Palaeontographical Society). Milne-Edwards and Haime. (16) 'Monograph of the Carboniferous Bivalve Entomostraca of Britain' (Palaeontographical Society). Rupert Jones, Kirkby, and George S. Brady. (17) 'Monograph of the Carboniferous Foraminifera of Britain' (Palaeontographical Society). H. B. Brady. (18) "On the Carboniferous Fossils of the West of Scotland"—'Trans. Geol. Soc.,' of Glasgow, vol. iii., Supplement. Young and Armstrong. (19) 'Poissons Fossiles.' Agassiz. (20) "Report on the Labyrinthodonts of the Coal-measures"—'British Association Report,' 1873. L. C. Miall. (21) 'Introduction to the Study of Palaeontological Botany.' John Hutton Balfour. (22) 'Traite de Paleontologie Vegetale.' Schimper. (23) 'Fossil Flora.' Lindley and Hutton. (24) 'Histoire des Vegetaux Fossiles.' Brongniart. (25) 'On Calamites and Calamodendron' (Monographs of the Palaeontographical Society). Binney. (26) 'On the Structure of Fossil Plants found in the Carboniferous Strata' (Palaeontographical Society). Binney.

Also numerous memoirs by Huxley, Davidson, Martin Duncan, Professor Young, John Young, R. Etheridge, jun., Baily, Carruthers, Dawson, Binney, Williamson, Hooker, Jukes, Geikie, Rupert Jones, Salter, and many other British and foreign observers.



CHAPTER XIV.

THE PERMIAN PERIOD.

The Permian formation closes the long series of the Palaeozoic deposits, and may in some respects be considered as a kind of appendix to the Carboniferous system, to which it cannot be compared in importance, either as regards the actual bulk of its sediments or the interest and variety of its life-record. Consisting, as it does, largely of red rocks—sandstones and marls—for the most part singularly destitute of organic remains, the Permian rocks have been regarded as a lacustrine or fluviatile deposit; but the presence of well-developed limestones with indubitable marine remains entirely negatives this view. It is, however, not improbable that we are presented in the Permian formation, as known to us at present, with a series of sediments laid down in inland seas of great extent, due to the subsidence over large areas of the vast land-surfaces of the Coal-measures. This view, at any rate, would explain some of the more puzzling physical characters of the formation, and would not be definitely negatived by any of its fossils.

A large portion of the Permian series, as already remarked, consists of sandstones and marls, deeply reddened by peroxide of iron, and often accompanied by beds of gypsum or deposits of salt. In strata of this nature few or no fossils are found; but their shallow-water origin is sufficiently proved by the presence of the footprints of terrestrial animals, accompanied in some cases by well-defined "ripple-marks." Along with these are occasionally found massive breccias, holding larger or smaller blocks derived from the older formations; and these have been supposed to represent an old "boulder-clay," and thus to indicate the prevalence of an arctic climate. Beds of this nature must also have been deposited in shallow water. In all regions, however, where the Permian formation is well developed, one of its most characteristic members is a Magnesian limestone, often highly and fantastically concretionary, but containing numerous remains of genuine marine animals, and clearly indicating that it was deposited beneath a moderate depth of salt water.

It is not necessary to consider here whether this formation can be retained as a distinct division of the geological series. The name of Permian was given to it by Sir Roderick Murchison, from the province of Perm in Russia, where rocks of this age are extensively developed. Formerly these rocks were grouped with the succeeding formation of the Trias under the common name of "New Red Sandstone." This name was given them because they contain a good deal of red sandstone, and because they are superior to the Carboniferous rocks, while the Old Red Sandstone is inferior. Nowadays, however, the term "New Red Sandstone" is rarely employed, unless it be for red sandstones and associated rocks, which are seen to overlie the Coal-measures, but which contain no fossils by which their exact age may be made out. Under these circumstances, it is sometimes convenient to employ the term "New Red Sandstone." The New Red, however, of the older geologists, is now broken up into the two formations of the Permian and Triassic rocks—the former being usually considered as the top of the Palaeozoic series, and the latter constituting the base of the Mesozoic.

In many instances, the Permian rocks are seen to repose unconformably upon the underlying Carboniferous, from which they can in addition be readily separated by their lithological characters. In other instances, however, the Coal-measures terminate upwards in red rocks, not distinguishable by their mineral characters from the Permian; and in other cases no physical discordance between the Carboniferous and Permian strata can be detected. As a general rule, also, the Permian rocks appear to pass upwards conformably into the Trias. The division, therefore, between the Permian and Triassic rocks, and consequently between the Palaeozoic and Mesozoic series, is not founded upon any conspicuous or universal physical break, but upon the difference in life which is observed in comparing the marine animals of the Carboniferous and Permian with those of the Trias. It is to be observed, however, that this difference can be solely due to the fact that the Magnesian Limestone of the Permian series presents us with only a small, and not a typical, portion of the marine deposits which must have been accumulated in some area at present unknown to us during the period which elapsed between the formation of the great marine limestones of the Lower Carboniferous and the open-sea and likewise calcareous sediments of the Middle Trias.

The Permian rocks exhibit their most typical features in Russia and Germany, though they are very well developed in parts of Britain, and they occur in North America. When well developed, they exhibit three main divisions: a lower set of sandstones, a middle group, generally calcareous, and an upper series of sandstones, constituting respectively the Lower, Middle, and Upper Permians.

In Russia, Germany, and Britain, the Permian rocks consist of the following members:—

1. The Lower Permians, consisting mainly of a great series of sandstones, of different colours, but usually red. The base of this series is often constituted by massive breccias with included fragments of the older rocks, upon which they may happen to repose; and similar breccias sometimes occur in the upper portion of the series as well. The thickness of this group varies a good deal, but may amount to 3000 or 4000 feet.

2. The Middle Permians, consisting, in their typical development, of laminated marls, or "marl-slate," surmounted by beds of magnesian limestone (the "Zechstein" of the German geologists). Sometimes the limestones are degenerate or wholly deficient, and the series may consist of sandy shales and gypsiferous clays. The magnesian limestone, however, of the Middle Permians is, as a rule, so well marked a feature that it was long spoken of as the Magnesian Limestone.

3. The Upper Permians, consisting of a series of sandstones and shales, or of red or mottled marls, often gypsiferous, and sometimes including beds of limestone.

In North America, the Permian rocks appear to be confined to the region west of the Mississippi, being especially well developed in Kansas. Their exact limits have not as yet been made out, and their total thickness is not more than a few hundred feet. They consist of sandstones, conglomerates, limestones, marls, and beds of gypsum.

The following diagrammatic section shows the general sequence of the Permian deposits in the north of England, where the series is extensively developed (fig. 133):—



The record of the life of the Permian period is but a scanty one, owing doubtless to the special peculiarities of such of the deposits of this age with which we are as yet acquainted. Red rocks are, as a general rule, more or less completely unfossiliferous, and sediments of this nature are highly characteristic of the Permian. Similarly, magnesian limestones are rarely as highly charged with organic remains as is the case with normal calcareous deposits, especially when they have been subjected to concretionary action, as is observable to such a marked extent in the Permian limestones. Nevertheless, much interest is attached to the organic remains, as marking a kind of transition-period between the Palaeozoic and Mesozoic epochs.



The plants of the Permian period, as a whole, have a distinctly Palaeozoic aspect, and are far more nearly allied to those of the Coal-measures than they are to those of the earlier Secondary rocks; though the Permian species are mostly distinct from the Carboniferous, and there are some new genera. Thus, we find species of Lepidodendron, Calamites, Equisetites, Asterophyllites, Annularia, and other highly characteristic Carboniferous genera. On the other hand, the Sigillariods of the Coal seem to have finally disappeared at the close of the Carboniferous period. Ferns are abundant in the Permian rocks, and belong for the most part to the well-known Carboniferous genera Alethopteris, Neuropteris, Sphenopteris, and Pecopteris. There are also Tree-ferns referable to the ancient genus Psaronius. The Conifers of the Permian period are numerous, and belong in part to Carboniferous genera. A characteristic genus, however, is Walchia (fig. 134), distinguished by its lax short leaves. This genus, though not exclusively Permian, is mainly so, the best-known species being the W. Piniformis. Here, also, we meet with Conifers which produce true cones, and which differ, therefore, in an important degree from the Taxoid Conifers of the Coal-measures. Besides Walchia, a characteristic form of these is the Ullmania selaginoides, which occurs in the Magnesian Limestone of Durham, the Middle Permian of Westmorland, and the "Kupfer-schiefer" of Germany. The group of the Cycads, which we shall subsequently find to be so characteristic of the vegetation of the Secondary period, is, on the other hand, only doubtfully represented in the Permian deposits by the singular genus Noeggerathia.

The Protozoans of the Permian rocks are few in number, and for the most part imperfectly known. A few Foraminifera have been obtained from the Magnesian Limestone of England, and the same formation has yielded some ill-understood Sponges. It does not seem, however, altogether impossible that some of the singular "concretions" of this formation may ultimately prove to have an organic structure, though others would appear to be clearly of purely inorganic origin. From the Permian of Saxony, Professor Geinitz has described two species of Spongillopsis, which he believes to be most nearly allied to the existing fresh-water Sponges (Spongilla). This observation has an interest as bearing upon the mode of deposition and origin of the Permian sediments.

The Coelenterates are represented in the Permian by but a few Corals. These belong partly to the Tabulate and partly to the Rugose division; but the latter great group, so abundantly represented in Silurian, Devonian, and Carboniferous seas, is now extraordinarily reduced in numbers, the British strata of this age yielding only species of the single genus Polycoelia. So far, therefore, as at present known, all the characteristic genera of the Rugose Corals of the Carboniferous had become extinct before the deposition of the limestones of the Middle Permian.

The Echinoderms are represented by a few Crinoids, and by a Sea-urchin belonging to the genus Eocidaris. The latter genus is nearly allied to the Archoeocidaris of the Carboniferous, so that this Permian form belongs to a characteristically Palaeozoic type.

A few Annelides (Spirorbis, Vermilia, &c.) have been described, but are of no special importance. Amongst the Crustaceans, however, we have to note the total absence of the great Palaeozoic group of the Trilobites; whilst the little Ostracoda and Phyllopods still continue to be represented. We have also to note the first appearance here of the "Short-tailed" Decapods or Crabs (Brachyura), the highest of all the groups of Crustacea, in the person of Hemitrochiscus paradoxus, an extremely minute Crab from the Permian of Germany.



Amongst the Mollusca, the remains of Polyzoa may fairly be said to be amongst the most abundant of all the fossils of the Permian formation, The principal forms of these are the fronds of the Lace-corals (Fenestella, Retepora, and Synocladia), which are very abundant in the Magnesian Limestone of the north of England, and belong to various highly characteristic species (such as Fenestella retiformis, Retepora Ehrenbergi, and Synocladia virgulacea). The Brachiopoda are also represented in moderate numbers in the Permian. Along with species of the persistent genera Discina, Crania, and Lingula, we still meet with representatives of the old groups Spirifera, Athyris, and Streptorhynchus; and the Carboniferous Productoe yet survive under well-marked and characteristic types, though in much-diminished numbers. The species of Brachiopods here figured (fig. 135) are characteristic of the Magnesian Limestone in Britain and of the corresponding strata on the Continent. Upon the whole, the most characteristic Permian Brachiopods belong to the genera Producta, Strophalosia, and Camarophoria.

The Bivalves (Lamellibranchiata) have a tolerably varied development in the Permian rocks; but nearly all the old types, except some of those which occur in the Carboniferous, have now disappeared. The principal Permian Bivalves belong to the groups of the Pearl Oysters (Aviculidoe) and the Trigoniadoe, represented by genera such as Bakewellia and Schizodus; the true Mussels (Mytilidoe), represented by species which have been referred to Mytilus itself; and the Arks (Arcadoe), represented by species of the genera Arca (fig. 136) and Byssoarca. The first and last of these three families have a very ancient origin; but the family of the Trigoniadoe, though feebly represented at the present day, is one which attained its maximum development in the Mesozoic period.



The Univalves (Gasteropoda) are rare, and do not demand special notice. It may be observed, however, that the Palaeozoic genera Euomphalus, Murchisonia, Loxonema, and Macrocheilus are still in existence, together with the persistent genus Pleurotomaria. Pteropods of the old genera Theca and Conularia have been discovered; but the first of these characteristically Palaeozoic types finally dies out here, and the second only survives but a short time longer. Lastly, a few Cephalopods have been found, still wholly referable to the Tetrabranchiate group, and belonging to the old genera Orthoceras and Cyrtoceras and the long-lived Nautilus.



Amongst Vertebrates, we meet in the Permian period not only with the remains of Fishes and Amphibians, but also, for the first time, with true Reptiles. The Fishes are mainly Ganoids, though there are also remains of a few Cestraciont Sharks. Not only are the Ganoids still the predominant group of Fishes, but all the known forms possess the unsymmetrical ("heterocercal") tail which is so characteristic of the Palaeozoic Ganoids. Most of the remains of the Permian Fishes have been obtained from the "Marl-slate" of Durham and the corresponding "Kupfer-schiefer" of Germany, on the horizon of the Middle Permian; and the principal genera of the Ganoids are Paloeoniscus and Platysomus (fig. 137).

The Amphibians of the Permian period belong principally to the order of the Labyrinthodonts, which commenced to be represented in the Carboniferous, and has a large development in the Trias. Under the name, however, of Paloeosiren Beinerti, Professor Geinitz has described an Amphibian from the Lower Permian of Germany, which he believes to be most nearly allied to the existing "Mud-eel" (Siren lacertina) of North America, and therefore to be related to the Newts and Salamanders (Urodela).

]

Finally, we meet in the Permian deposits with the first undoubted remains of true Reptiles. These are distinguished, as a class, from the Amphibians, by the fact that they are air-breathers throughout the whole of their life, and therefore are at no time provided with gills; whilst they are exempt from that metamorphosis which all the Amphibia undergo in early life, consequent upon their transition from an aquatic to a more or less purely aerial mode of respiration. Their skeleton is well ossified; they usually have horny or bony plates, singly or in combination, developed in the skin; and their limbs (when present) are never either in the form of fins or wings, though sometimes capable of acting in either of these capacities, and liable to great modifications of form and structure. Though there can be no doubt whatever as to the occurrence of genuine Reptiles in deposits of unquestionable Permian age, there is still uncertainty as to the precise number of types which may have existed at this period. This uncertainty arises partly from the difficulty of deciding in all cases, whether a given bone be truely Labyrinthodont or Reptilian, but more especially from the confusion which exists at present between the Permian and the overlying Triassic deposits. Thus there are various deposits in different regions which have yielded the remains of Reptiles, and which cannot in the meanwhile be definitely referred either to the Permian series or to the Trias by clear stratigraphical or palaeontological evidence. All that can be done in such cases is to be guided by the characters of the Reptiles themselves, and to judge by their affinities to remains from known Triassic or Permian rocks to which of these formations the beds containing them should be referred; but it is obvious that this method of procedure is seriously liable to lead to error. In accordance, however, with this, the only available mode of determination in some cases, the remains of Thecodontosaurus and Palaeosaurus discovered in the dolomitic conglomerates near Bristol will be considered as Triassic, thus leaving Protorosaurus[20] as the principal and most important representative of the Permian Reptiles.[21] The type-species of the genus Protorusaurus is the P. Speneri(fig. 138) of the "Kupfer-schiefer" of Thuringia, but other allied species have been detected in the Middle Permian of Germany and the north of England. This Reptile attained a length of from three to four feet; and it has been generally referred to the group of the Lizards (Lacertilia), to which it is most nearly allied in its general structure, at the same time that it differs from all existing members of this group in the fact that its numerous conical and pointed teeth were implanted in distinct sockets in the jaws—this being a Crocodilian character. In other respects, however, Protorosaurus approximates closely to the living Monitors (Varanidoe); and the fact that the bodies of the vertebrae are slightly cupped or hollowed out at the ends would lead to the belief that the animal was aquatic in its habits. At the same time, the structure of the hind-limbs and their bony supports proves clearly that it must have also possessed the power of progression upon the land. Various other Reptilian bones have been described from the Permian formation, of which some are probably really referable to Labyrinthodonts, whilst others are regarded by Professor Owen as referable to the order of the "Theriodonts," in which the teeth are implanted in sockets, and resemble those of carnivorous quadrupeds in consisting of three groups in each jaw (namely, incisors, canines, and molars). Lastly, in red sandstones of Permian age in Dumfriesshire have been discovered the tracks of what would appear to have been Chelonians (Tortoises and Turtles); but it would not be safe to accept this conclusion as certain upon the evidence of footprints alone. The Chelichnus Duncani, however, described by Sir William Jardine in his magnificent work on the 'Ichnology of Annandale,' bears a great resemblance to the track of a Turtle.

[Footnote 20: Though commonly spelt as above, it is probable that the name of this Lizard was really intended to have been Proterosaurus—from the Greek proteros, first; and saura, lizard: and this spelling is followed by many writers.]

[Footnote 21: In an extremely able paper upon the subject (Quart. Journ. Geol. Soc., vol. xxvi.), Mr Etheridge has shown that there are good physical grounds for regarding the dolomitie conglomerate of Bristol as of Triassic age, and as probably corresponding in time with the Muschelkalk of the Continent.]

No remains of Birds or Quadrupeds have hitherto been detected in deposits of Permian age.

LITERATURE.

The following works may be consulted by the student with regard to the Permian formation and its fossils:—

(1) "On the Geological Relations and Internal Structure of the Magnesian Limestone and the Lower Portions of the New Red Sandstone Series, &c."—'Trans. Geol. Soc.,' ser. 2, vol. iii. Sedgwick. (2) 'The Geology of Russia in Europe.' Murchison, De Verneuil, and Von Keyserling. (3) 'Siluria,' Murchison. (4) 'Permische System in Sachsen.' Geinitz and Gutbier. (5) 'Die Versteinerungen des Deutschen Zechsteingebirges,' Geinitz. (6) 'Die Animalischen Ueberreste der Dyas.' Geinitz. (7) 'Monograph of the Permian Fossils of England' (Palaeontographical Society). King. (8) 'Monograph of the Permian Brachiopoda of Britain' (Palaeontographical Society). Davidson. (9) "On the Permian Rocks of the North-West of England and their Extension into Scotland"—'Quart. Journ. Geol. Soc.,' vol. xx. Murchison and Harkness. (10) 'Catalogue of the Fossils of the Permian System of the Counties of Northumberland and Durham.' Howse. (11) 'Petrefacta Germaniae.' Goldfuss. (12) 'Beitraege zur Petrefaktenkunde.' Munster. (13) 'Ein Beitrag zur Palaeontologie des Deutschen Zechsteingebirges.' Von Schauroth. (14) 'Saurier aus dem Kupfer-schiefer der Zechstein-formation.' Von Meyer. (15) 'Manual of Palaeontology.' Owen. (16) 'Recherches sur les Poissons Fossiles.' Agassiz. (17) 'Ichnology of Annandale.' Sir William Jardine. (18) 'Die Fossile Flora der Permischen Formation.' Goeppert. (19) 'Genera et Species Plantarum Fossilium.' Unger. (20) "On the Red Rocks of England of older Date than the Trias" —'Quart. Journ. Geol. Soc.,' vol. xxvii. Ramsay.



CHAPTER XV.

THE TRIASSIC PERIOD.

We come now to the consideration of the great Mesozoic, or Secondary series of formations, consisting, in ascending order, of the Triassic, Jurassic, and Cretaceous systems. The Triassic group forms the base of the Mesozoic series, and corresponds with the higher portion of the New Red Sandstone of the older geologists. Like the Permian rocks, and as implied by its name, the Trias admits of a subdivision into three groups—a Lower, Middle, and Upper Trias. Of these sub-divisions the middle one is wanting in Britain; and all have received German names, being more largely and typically developed in Germany than in any other country. Thus, the Lower Trias is known as the Bunter Sandstein; the Middle Trias is called the Muschelkalk; and the Upper Trias is known as the Keuper.

I. The lowest division of the Trias is known as the Bunter Sandstein (the Gres bigarre of the French), from the generally variegated colours of the beds which compose it (German, bunt, variegated). The Bunter Sandstein of the continent of Europe consists of red and white sandstones, with red clays, and thin limestones, the whole attaining a thickness of about 1500 feet. The term "marl" is very generally employed to designate the clays of the Lower and Upper Trias; but the term is inappropriate, as they may contain no lime, and are therefore not always genuine marls. In Britain the Bunter Sandstein consists of red and mottled sandstones, with unconsolidated conglomerates, or "pebble-beds," the whole having a thickness of 1000 to 2000 feet. The Bunter Sandstein, as a rule, is very barren of fossils.

II. The Middle Trias is not developed in Britain, but it is largely developed in Germany, where it constitutes what is known as the Muschelkalk (Germ. Muschel, mussel; kalk, limestone), from the abundance of fossil shells which it contains. The Muschelkalk (the Calcaire coquillier of the French) consists of compact grey or yellowish limestones, sometimes dolomitic, and including occasional beds of gypsum and rock-salt.

III. The Upper Trias, or Keuper (the Marnes irisees of the French), as it is generally called, occurs in England; but is not so well developed as it is in Germany. In Britain, the Keuper is 1000 feet or more in thickness, and consists of white and brown sandstones, with red marls, the whole topped by red clays with rock-salt and gypsum.

The Keuper in Britain is extremely unfossiliferous; but it passes upwards with perfect conformity into a very remarkable group of beds, at one time classed with the Lias, and now known under the names of the Penarth beds (from Penarth, in Glamorganshire), the Rhaetic beds (from the Rhaetic Alps), or the Avicula contorta beds (from the occurrence in them of great numbers of this peculiar Bivalve). These singular beds have been variously regarded as the highest beds of the Trias, or the lowest beds of the Lias, or as an intermediate group. The phenomena observed on the Continent, however, render it best to consider them as Triassic, as they certainly agree with the so-called Upper St Cassian or Koessen beds which form the top of the Trias in the Austrian Alps.

The Penarth beds occur in Glamorganshire, Gloucestershire, Warwickshire, Staffordshire, and the north of Ireland; and they generally consist of a small thickness of grey marls, white limestones, and black shales, surmounted conformably by the lowest beds of the Lias. The most characteristic fossils which they contain are the three Bivalves Cardium Rhoeticum, Avicula contorta, and Pecten Valoniensis; but they have yielded many other fossils, amongst which the most important are the remains of Fishes and small Mammals (Microlestes).

In the Austrian Alps the Trias terminates upwards in an extraordinary series of fossiliferous beds, replete with marine fossils. Sir Charles Lyell gives the following table of these remarkable deposits:—

Strata below the Lias in the Austrian Alps, in descending order.

/ Grey and black limestone, with calcareous marls having a thickness of about 50 feet. Among the fossils, Brachiopoda 1. Koessen beds. very numerous; some few species common (Synonyms, Upper to the genuine Lias; many peculiar. St Cassian beds of < Avicula contorta, Pecten Valoniensis, Escher and Merian.) Cardium Rhoeticum, Avicula inoequivalvis, Spirifer Muensteri, Dav. Strata containing the above fossils alternate with the Dachstein beds, lying next below.

/ White or greyish limestone, often in beds three or four feet thick. Total thickness of the formation above 2000 feet. Upper part fossiliferous, with some strata 2. Dachstein beds. < composed of corals (Lithodendron.) Lower portion without fossils. Among the characteristic shells are Hemicardium Wulfeni, Megalodon triqueler, and other large bivalves.

/ Red, pink, or white marbles, from 800 to 1000 feet in thickness, containing more than 800 species of marine fossils, for 3. Hallstadt beds the most part mollusca. Many species of (or St Cassian). < Orthoceras. True Ammonites, besides Ceratites and Goniatites, Belemnites (rare), Porcellia, Pleurotomania, Trochus, Monotis salinaria, &c.

/ A. Black and grey Among the fossils 4. A. Guttenstein beds. limestone 150 feet are Ceratites B. Werfen beds, base thick, alternating cassianus, of Upper Trias? with the underlying Myacites Lower Trias of fassaensis, some geologists. B. Red and green Naticella shale and sandstone, costata, &c. with salt and gypsum./

In the United States, rocks of Triassic age occur in several areas between the Appalachians and the Atlantic seaboard; but they show no such triple division as in Germany, and their exact place in the system is uncertain. The rocks of these areas consist of red sandstones, sometimes shaly or conglomeratic, occasionally with beds of impure limestone. Other more extensive areas where Triassic rocks appear at the surface, are found west of the Mississippi, on the slopes of the Rocky Mountains, where the beds consist of sandstones and gypsiferous marls. The American Trias is chiefly remarkable for having yielded the remains of a small Marsupial (Dromatherium), and numerous footprints, which have generally been referred to Birds (Brontozoum), along with the tracks of undoubted Reptiles (Otozoum, Anisopus, &c.)

The subjoined section (fig. 139) expresses, in a diagrammatic manner, the general sequence of the Triassic rocks when fully developed, as, for example, in the Bavarian Alps:—



With regard to the life of the Triassic period, we have to notice a difference as concerns the different members of the group similar to that which has been already mentioned in connection with the Permian formation. The arenaceous deposits of the series, namely, resemble those of the Permian, not only in being commonly red or variegated in their colour, but also in their conspicuous paucity of organic remains. They for the most part are either wholly unfossiliferous, or they contain the remains of plants or the bones of reptiles, such as may easily have been drifted from some neighbouring shore. The few fossils which may be considered as properly belonging to these deposits are chiefly Crustaceans (Estheria) or Fishes, which may well have lived in the waters of estuaries or vast inland seas. We may therefore conclude, with considerable probability, that the barren sandy and marly accumulations of the Bunter Sandstein and Lower Keuper were not laid down in an open sea, but are probably brackish-water deposits, formed in estuaries or land-locked bodies of salt water. This at any rate would appear to be the case as regards these members of the series as developed in Britain and in their typical areas on the continent of Europe; and the origin of most of the North American Trias would appear to be much the same. Whether this view be correct or not, it is certain that the beds in question were laid down in shallow water, and in the immediate vicinity of land, as shown by the numerous drifted plants which they contain and the common occurrence in them of the footprints of air-breathing animals (Birds, Reptiles, and Amphibians). On the other hand, the middle and highest members of the Trias are largely calcareous, and are replete with the remains of undoubted marine animals. There cannot, therefore, be the smallest doubt but that the Muschelkalk and the Rhaetic or Koessen beds were slowly accumulated in an open sea, of at least a moderate depth; and they have preserved for us a very considerable selection from the marine fauna of the Triassic period.



The plants of the Trias are, on the whole, as distinctively Mesozoic in their aspect as those of the Permian are Palaeozoic. In spite, therefore, of the great difficulty which is experienced in effecting a satisfactory stratigraphical separation between the Permian and the Trias, we have in this fact a proof that the two formations were divided by an interval of time sufficient to allow of enormous changes in the terrestrial vegetation of the world. The Lepidodendroids, Asterophyllites, and Annularioe, of the Coal and Permian formations, have now apparently wholly disappeared: and the Triassic flora consists mainly of Ferns, Cycads, and Conifers, of which only the two last need special notice. The Cycads (fig. 140) are true exogenous plants, which in general form and habit of growth present considerable resemblance to young Palms, but which in reality are most nearly related to the Pines and Firs (Coniferoe). The trunk is unbranched, often much shortened, and bears a crown of feathery pinnate fronds. The leaves are usually "circinate"—they unroll in expanding, like the fronds of ferns. The seeds are not protected by a seed-vessel, but are borne upon the edge of altered leaves, or are carried on the scales of a cone. All the living species of Cycads are natives of warm countries, such as South America, the West Indies, Japan, Australia, Southern Asia, and South Africa. The remains of Cycads, as we have seen, are not known to occur in the Coal formation, or only to a very limited extent towards its close; nor are they known with certainty as occurring in Permian deposits. In the Triassic period, however, the remains of Cycads belonging to such genera as Pterophyllum (fig. 141, b), Zamites, and Podozamites (fig. 141, c), are sufficiently abundant to constitute quite a marked feature in the vegetation; and they continue to be abundantly represented throughout the whole Mesozoic series. The name "Age of Cycads," as applied to the Secondary epoch, is therefore, from a botanical point of view, an extremely appropriate one. The Conifers of the Trias are not uncommon, the principal form being Veltzia (fig. 141, a), which possesses some peculiar characters, but would appear to be most nearly related to the recent Cypresses.



As regards the Invertebrate animals of the Trias, our knowledge is still principally derived from the calcareous beds which constitute the centre of the system (the Muschelkalk) on the continent of Europe, and from the St Cassain and Rhaetic beds still higher in the series; whilst some of the Triassic strata of California and Nevada have likewise yielded numerous remains of marine Invertebrates. The Protozoans are represented by Foraminifera and Sponges, and the Coelenterates by a small number of Corals; but these require no special notice. It may be mentioned, however, that the great Palaeozoic group of the Rugose corals has no known representative here, its place being taken by corals of Secondary type (such as Montlivaltia, Synastoea, &c.)

The Echinoderms are represented principally by Crinoids, the remains of which are extremely abundant in some of the limestones. The best-known species is the famous "Lily-Encrinite" (Encrinus liliiformis, fig. 142), which is characteristic of the Muschelkalk. In this beautiful species, the flower-like head is supported upon a rounded stem, the joints of which are elaborately articulated with one another; and the fringed arms are composed each of a double series of alternating calcareous pieces. The Palaeozoic Urchins, with their supernumerary rows of plates, the Cystideans, and the Pentremites have finally disappeared; but both Star-fishes and Brittle-stars continue to be represented. One of the latter—namely, the Aspidura loricata of Goldfuss (fig. 143)—is highly characteristic of the Muschelkalk.



The remains of Articulate Animals are not very abundant in the Trias, if we except the bivalved cases of the little Water-fleas (Ostracoda), which are occasionally very plentiful. There are also many species of the horny, concentrically-striated valves of the Estherioe (see fig. 122, b), which might easily be taken for small Bivalve Molluscs. The "Long-tailed" Decapods of the type of the Lobster, are not without examples but they become much more numerous in the succeeding Jurassic period. Remains of insects have also been discovered.

Amongst the Mollusca we have to note the disappearance, amongst the lower groups, of many characteristic Palaeozoic types. Amongst the Polyzoans, the characteristic "Lace-corals," Fenestella, Retepora,[22] Synocladia, Polypora, &c., have become apparently extinct. The same is true of many of the ancient types of Brachiopods, and conspicuously so of the great family of the Productidoe, which played such an important part in the seas of the Carboniferous and Permian periods.

[Footnote 22: The genus Retefora is really a recent one, represented by living forms; and the so-called Reteporoe of the Palaeozoic rocks should properly receive another name (Phyllopora), as being of a different nature. The name Retepora has been here retained for these old forms simply in accordance with general usage.]

[Illustraton: Fig. 144. Triassic Lamellibranchs. a, Daonella (Halobia) Lommelli; b, Pecten Valoniensis; c, Myophoria lineata; d. Cardium Rhoeticum; e. Avicula contorta; f. Avicula socialis.]

_Bivalves_ (_Lamellibranchiata_) and _Univalves_ (_Gasteropoda_) are well represented in the marine beds of the Trias, and some of the former are particularly characteristic either of the formation as a whole or of minor subdivisions of it. A few of these characteristic species are figured in the accompanying illustration (fig. 144). Bivalve shells of the genera _Daonella_ (fig. 144, a) and _Halobia_ (_Monotis_) are very abundant, and are found in the Triassic strata of almost all regions. These groups belong to the family of the Pearl-oysters (_Aviculidoe_), and are singular from the striking resemblance borne by some of their included forms to the _Strophomenoe amongst the Lamp-shells, though, of course, no real relation exists between the two. The little Pearl-oyster, _Avicula socialis_ (fig. 144, f), is found throughout the greater part of the Triassic series, and is especially abundant in the Muschelkalk. The genus _Myophoria_ (fig. 144, c), belonging to the _Trigoniadoe_, and related therefore to the Permian _Schizodus_, is characteristically Triassic, many species of the genus being known in deposits of this age. Lastly, the so-called "Rhaetic" or "Koessen" beds are characterised by the occurrence in them of the Scallop, _Pecten Valoniensis_ (fig. 144, b); the small Cockle, _Cardium Rhoeticum_ (fig. 144, d); and the curiously-twisted Pearl-oyster, _Avicula contorta_ (fig. 144, e)—this last Bivalve being so abundant that the strata in question are often spoken of as the "Avicula contorta beds."



Passing over the groups of the Heteropods and Pteropods, we have to notice the Cephalopoda, which are represented in the Trias not only by the chambered shells of Tetrabranchiates, but also, for the first time, by the internal skeletons of Dibranchiate forms. The Trias, therefore, marks the first recognised appearance of true Cuttle-fishes. All the known examples of these belong to the great Mesozoic group of the Belemnitidoe; and as this family is much more largely developed in the succeeding Jurassic period, the consideration of its characters will be deferred till that formation is treated of. Amongst the chambered Cephalopods we find quite a number of the Palaeozoic Orthoceratites, some of them of considerable size, along with the ancient Cyrtoceras and Goniatites; and these old types, singularly enough, occur in the higher portion of the Trias (St Cassian beds), but have, for some unexplained reason, not yet been recognised in the lower and equally fossiliferous formation of the Muschelkalk. Along with these we meet for the first time with true Ammonites, which fill such an extensive place in the Jurassic seas, and which will be spoken of hereafter. The form, however, which is most characteristic of the Trias is Ceratites (fig. 145). In this genus the shell is curved into a flat spiral, the volutions of which are in contact; and it further agrees with both Goniatites and Ammonites in the fact that the septa or partitions between the air-chambers are not simple and plain (as in the Nautilus and its allies), but are folded and bent as they approach the outer wall of the shell. In the Goniatite these foldings of the septa are of a simply lobed or angulated nature, and in the Ammonite they are extremely complex; whilst in the Ceratite there is an intermediate state of things, the special feature of which is, that those foldings which are turned towards the mouth of the shell are merely rounded, whereas those which are turned away from the mouth are characteristically toothed. The genus Ceratites, though principally Triassic, has recently been recognised in strata of Carboniferous age in India.

From the foregoing it will be gathered that one of the most important points in connection with the Triassic Mollusca is the remarkable intermixture of Palaeozoic and Mesozoic types which they exhibit. It is to be remembered, also, that this intermixture has hitherto been recognised, not in the Middle Triassic limestones of the Muschelkalk, in which—as the oldest Triassic beds with marine fossils—we should naturally expect to find it, but in the St Cassian beds, the age of which is considerably later than that of the Muschelkalk. The intermingling of old and new types of Shell-fish in the Upper Trias is well brought out in the annexed table, given by Sir Charles Lyell in his 'Student's Elements of Geology' (some of the less important forms in the table being omitted here):—

GENERA OF FOSSIL MOLLUSCA IN THE ST CASSIAN AND HALLSTADT BEDS.

Common to Characteristic of Common to Older Rocks. Triassic Rocks Newer Rocks. Orthoceras. Ceratites. Ammonites. Bactrites. Cochloceras. Chemnitzia. Macrocheilus. Rhabdoceras. Cerithium. Loxonema. Aulacoceras. Monodonta. Holopella. Naticella. Sphoera. Murchisonia. Platystoma. Cardita. Porcellia. Halobia. Myoconcha. Athyris. Hoernesia. Hinnites. Retzia. Koninckia. Monotis. Cyrtina. Scoliostoma. Plicatula. Euomphalus. Myophoria. Pachyrisma. (The last two are Thecidium. principally but not exclusively Triassic.)

Thus, to emphasise the more important points alone, the Trias has yielded, amongst the Gasteropods, the characteristically Palaeozoic Loxonema, Holopella, Murchisonia, Euomphalus, and Porcellia, along with typically Triassic forms like Platystoma and Scoliostoma, and the great modern groups Chemnitzia and Cerithium. Amongst the Bivalves we find the Palaeozoic Megalodon side by side with the Triassic Halobia and Myophoria, these being associated with the Carditoe, Hinnites, Plicatuloe, and Trigonioe of later deposits. The Brachiopods exhibit the Palaeozoic Athyris, Retzia, and Cyrtina, with the Triassic Koninckia and the modern Thecidium. Finally, it is here that the ancient genera Orthoceras, Cyrtoceras, and Goniatites make their last appearance upon the scene of life, the place of the last of these being taken by the more complex and almost exclusively Triassic Ceratites, whilst the still more complex genus Ammonites first appears here in force, and is never again wanting till we reach the close of the Mesozoic period. The first representatives of the great Secondary family of the Belemnites are also recorded from this horizon.



Amongst the Vertebrate Animals of the Trias, the Fishes are represented by numerous forms belonging to the Ganoids and the Placoids. The Ganoids of the period are still all provided with unsymmetrical ("heterocercal") tails, and belong principally to such genera as Paloeoniscus and Catopterus. The remains of Placoids are in the form of teeth and spines, the two principal genera being the two important Secondary groups Acrodus and Hybodus. Very nearly at the summit of the Trias in England, in the Rhaetic series, is a singular stratum, which is well known as the "bone-bed," from the number of fish-remains which it contains. More interesting, however, than the above, are the curious palate-teeth of the Trias, upon which Agassiz founded the genus Ceratodus. The teeth of Ceratodus (fig. 146) are singular flattened plates, composed of spongy bone beneath, covered superficially with a layer of enamel. Each plate is approximately triangular, one margin (which we now know to be the outer one) being prolonged into prongs or conical prominences, whilst the surface is more or less regularly undulated. Until recently, though the master-mind of Agassiz recognised that these singular bodies were undoubtedly the teeth of fishes, we were entirely ignorant as to their precise relation to the animal, or as to the exact affinities of the fish thus armed. Lately, however, there has been discovered in the rivers of Queensland (Australia) a living species of Ceratodus (C. Fosteri, fig. 147), with teeth precisely similar to those of its Triassic predecessor; and we thus have become acquainted with the use of these structures and the manner in which they were implanted in the mouth. The palate carries two of these plates, with their longer straight sides turned towards each other, their sharply-sinuated sides turned outwards, and their short straight sides or bases directed backwards. Two similar plates in the lower jaw correspond to the upper, their undulated surfaces fitting exactly to those of the opposite teeth. There are also two sharp-edged front teeth, which are placed in the front of the mouth in the upper jaw; but these have not been recognised in the fossil specimens. The living Ceratodus feeds on vegetable matters, which are taken up or tom off from plants by the sharp front teeth, and then partially crushed between the undulated surfaces of the back teeth (Guenther); and there need be little doubt but that the Triassic Ceratodi followed a similar mode of existence. From the study of the living Ceratodus, it is certain that the genus belongs to the same group as the existing Mud-fishes (Dipnoi); and we therefore learn that this, the highest, group of the entire class of Fishes existed in Triassic times under forms little or not at all different from species now alive; whilst it has become probable that the order can be traced back into the Devonian period.



The Amphibians of the Trias all belong to the old order of the Labyrinthodonts, and some of them are remarkable for their gigantic dimensions. They were first known by their footprints, which were found to occur plentifully in the Triassic sandstones of Britain and the continent of Europe, and which consisted of a double series of alternately-placed pairs of hand-shaped impressions, the hinder print of each pair being much larger than the one in front (fig. 148). So like were these impressions to the shape of the human hand, that the at that time unknown animal which produced them was at once christened Cheirotherium, or "Hand-beast." Further discoveries, however, soon showed that the footprints of Cheirotherium were really produced by species of Amphibians which, like the existing Frogs, possessed hind-feet of a much larger size than the fore-feet, and to which the name of Labyrinthodonts was applied in consequence of the complex microscopic structure of the teeth (fig. 149). In the essential details of their structure, the Triassic Labyrinthodonts did not differ materially from their predecessors in the Coal-measures and Permian rocks. They possessed the same frog-like skulls (fig. 150), with a lizard-like body, a long tail, and comparatively feeble limbs. The hind-limbs were stronger and longer than the fore-limbs, and the lower surface of the body was protected by an armour of bony plates. Some of the Triassic Labyrinthodonts must have attained dimensions utterly unapproached amongst existing Amphibians, the skull of Labyrinthodon Joegeri (fig. 150) being upwards of three feet in length and two feet in breadth. Restorations of some of these extraordinary creatures have been attempted in the guise of colossal Frogs; but they must in reality have more closely resembled huge Newts.

Remains of Reptiles are very abundant in Triassic deposits, and belong to very varied types. The most marked feature, in fact, connected with the Vertebrate fauna of the Trias, and of the Secondary rocks in general, is the great abundance of Reptilian life. Hence the Secondary period is often spoken of as the "Age of Reptiles." Many of the Triassic reptiles depart widely in their structure from any with which we are acquainted as existing on the earth at the present day, and it is only possible here to briefly note some of the more important of these ancient forms. Amongst the group of the Lizards (Lacertilia), represented by Protorosaurus in the older Permian strata, three types more or less certainly referable to this order may be mentioned. One of these is a small reptile which was found many years ago in sandstones near Elgin, in Scotland, and which excited special interest at the time in consequence of the fact that the strata in question were believed to belong to the Old Red Sandstone formation. It is, however, now certain that the Elgin sandstones which contain Telerpeton Elginense, as this reptile is termed, are really to be regarded as of Triassic age. By Professor Huxley, Telerpeton is regarded as a Lizard, which cannot be considered as "in any sense a less perfectly-organised creature than the Gecko, whose swift and noiseless run over walls and ceilings surprises the traveller in climates warmer than our own." The "Elgin Sandstones" have also yielded another Lizard, which was originally described by Professor Huxley under the name of Hyperodapedon, the remains of the same genus having been subsequently discovered in Triassic strata in India and South Africa. The Lizards of this group must therefore have at one time enjoyed a very wide distribution over the globe; and the living Sphenodon of New Zealand is believed by Professor Huxley to be the nearest living ally of this family. The Hyperodapedon of the Elgin Sandstones was about six feet in length, with limbs adapted for terrestrial progression, but with the bodies of the vertebrae slightly biconcave, and having two rows of palatal teeth, which become worn down to the bone in old age. Lastly, the curious Rhynchosaurus of the Trias is also referred, by the eminent comparative anatomist above mentioned, to the order of the Lizards. In this singular reptile (fig. 151) the skull is somewhat bird-like, and the jaws appear to have been destitute of teeth, and to have been encased in a horny sheath like the beak of a Turtle or a Bird. It is possible, however, that the palate was furnished with teeth.



The group of the Crocodiles and Alligators (Crocadilia), distinguished by the fact that the teeth are implanted in distinct sockets and the skin more or less extensively provided with bony plates, is represented in the Triassic rocks by the Stagonolepis of the Elgin Sandstones. The so-called "Thecodont" reptiles (such as Belodon, Thecodontosaurus, and Paloeosaurus, fig. 152, c, d, e) are also nearly related to the Crocodiles, though it is doubtful if they should be absolutely referred to this group. In these reptiles, the teeth are implanted in distinct sockets in the jaws, their crowns being more or less compressed and pointed, "with trenchant and finely serrate margins" (Owen). The bodies of the vertebrae are hollowed out at both ends, but the limbs appear to be adapted for progression on the land. The genus Belodon (fig. 152, c) is known to occur in the Keuper of Germany and in America; and Paloeosaurus (fig. 153. e) has also been found in the Trias of the same region. Teeth of the latter, however, are found, along with remains of Thecodontosaurus (fig. 153, d), in a singular magnesian conglomerate near Bristol, which was originally believed to be of Permian age, but which appears to be undoubtedly Triassic.



The Trias has also yielded the remains of the great marine reptiles which are often spoken of collectively as the "Enaliosaurians" or "Sea-lizards," and which will be more particularly spoken of in treating of the Jurassic period, of which they are more especially characteristic. In all these reptiles the limbs are flattened out, the digits being enclosed in a continuous skin, thus forming powerful swimming-paddles, resembling the "flippers" of the Whales and Dolphins both in their general structure and in function. The tail is also long, and adapted to act as a swimming-organ; and there can be no doubt but that these extraordinary and often colossal reptiles frequented the sea, and only occasionally came to the land. The Triassic Enaliosaurs belong to a group of which the later genus Plesiosaurus is the type (the Sauropterygia). One of the best known of the Triassic genera is Nothosaurus (fig. 152, a), in which the neck was long and bird-like, the jaws being immensely elongated, and carrying numerous powerful conical teeth implanted in distinct sockets. The teeth in Simosaurus (152, b) are of a similar nature; but the orbits are of enormous size, indicating eyes of corresponding dimensions, and perhaps pointing to the nocturnal habits of the animal. In the singular Placodus, again, the teeth are in distinct sockets, but resemble those of many fishes in being rounded and obtuse (fig. 153), forming broad crushing plates adapted for the comminution of shell-fish. There is a row of these teeth all round the upper jaw proper, and a double series on the palate, but the lower jaw has only a single row of teeth. Placodus is found in the Muschelkalk, and the characters of its dental apparatus indicate that it was much more peaceful in its habits than its associates the Nothosaur and Simosaur.



The Triassic rocks of South Africa and India have yielded the remains of some extraordinary Reptiles, which have been placed by Professor Owen in a separate order under the name of Anomodontia. The two principal genera of this group are Dicynodon and Oudenodon, both of which appear to have been large Reptiles, with well-developed limbs, organised for progression upon the dry land. In Oudenodon (fig. 154, B) the jaws seem to have been wholly destitute of teeth, and must have been encased in a horny sheath, similar to that with which we are familiar in the beak of a Turtle. In Dicynodon (fig. 154, A), on the other hand, the front of the upper jaw and the whole of the lower jaw were destitute of teeth, and the front of the mouth must have constituted a kind of beak; but the upper jaw possessed on each side a single huge conical tusk, which is directed downwards, and must have continued to grow during the life of the animal.



It may be mentioned that the above-mentioned Triassic sandstones of South Africa have recently yielded to the researches of Professor Owen a new and unexpected type of Reptile, which exhibits some of the structural peculiarities which we have been accustomed to regard as characteristic of the Carnivorous quadrupeds. The Reptile in question has been named Cyanodraco, and it is looked upon by its distinguished discoverer as the type of a new order, to which he has given the name of Theriodontia. The teeth of this singular form agree with those of the Carnivorous quadrupeds in consisting of three distinct groups—namely, front teeth or incisors, eye teeth or canines, and back teeth or molars. The canines also are long and pointed, very much compressed, and having their lateral margins finely serrated, thus presenting a singular resemblance to the teeth of the extinct "Sabre-toothed Tiger" (Machairodus). The bone of the upper arm (humerus) further shows some remarkable resemblances to the same bone in the Carnivorous Mammals. As has been previously noticed, Professor Owen is of opinion that some of the Reptilian remains of the Permian deposits will also be found to belong to this group of the "Theriodonts."



Lastly, we find in the Triassic rocks the remains of Reptiles belonging to the great Mesozoic order of the Deinosauria. This order attains its maximum at a later period, and will be spoken of when the Jurassic and Cretaceous deposits come to be considered. The chief interest of the Triassic Reptiles of this group arises from the fact that they are known by their footprints as well as by their bones; and a question has arisen whether the supposed footprints of birds which occur in the Trias have not really been produced by Deinosaurs. This leads us, therefore, to speak at the same time as to the evidence which we have of the existence of the class of Birds during the Triassic period. No actual bones of any bird have as yet been detected in any Triassic deposit; but we have tolerably clear evidence of their existence at this time in the form of footprints. The impressions in question are found in considerable numbers in certain red sandstones of the age of the Trias in the valley of the Connecticut River, in the United States. They vary much in size, and have evidently been produced by many different animals walking over long stretches of estuarine mud and sand exposed at low water. The footprints now under consideration form a double series of single prints, and therefore, beyond all question, are the tracks of a biped—that is, of an animal which walked upon two legs. No living animals, save Man and the Birds, walk habitually on two legs; and there is, therefore, a prima facie presumption that the authors of these prints were Birds. Moreover, each impression consists of the marks of three toes turned forwards (fig. 155), and therefore are precisely such as might be produced by Wading or Cursorial Birds. Further, the impressions of the toes show exactly the same numerical progression in the number of the joints as is observable in living Birds—that is to say, the innermost of the three toes consists of three joints, the middle one of four, and the outer one of five joints. Taking this evidence collectively, it would have seemed, until lately, quite certain that these tracks could only have been formed by Birds. It has, however, been shown that the Deinosaurian Reptiles possess, in some cases at any rate, some singularly bird-like characters, amongst which is the fact that the animal possessed the power of walking, temporarily at least, on its hind-legs, which were much longer and stronger than the fore-limbs, and which were sometimes furnished with no more than three toes. As the bones and teeth of Deinosaurs have been found in the Triassic deposits of North America, it may be regarded as certain that some of the bipedal tracks originally ascribed to Birds must have really been produced by these Reptiles. It seems at the same time almost a certainty that others of the three-toed impressions of the Connecticut sandstones were in truth produced by Birds, since it is doubtful if the bipedal mode of progression was more than an occasional thing amongst the Deinosaurs, and the greater number of the many known tracks exhibit no impressions of fore-feet. Upon the whole, therefore, we may, with much probability, conclude that the great class of Birds (Aves) was in existence in the Triassic period. If this be so, not only must there have been quite a number of different forms, but some of them must have been of very large size. Thus the largest footprints hitherto discovered in the Connecticut sandstones are 22 inches long and 12 inches wide, with a proportionate length of stride. These measurements indicate a foot four times as large as that of the African Ostrich; and the animal which produced them—whether a Bird or a Deinosaur—must have been of colossal dimensions.



Finally, the Trias completes the tale of the great classes of the Vertebrate sub-kingdom by presenting us with remains of the first known of the true Quadrupeds or Mammalia. These are at present only known by their teeth, or, in one instance, by one of the halves of the lower jaw; and these indicate minute Quadrupeds, which present greater affinities with the little Banded Anteater (Myrmecobius fasciatus, fig. 158) of Australia than with any other living form. If this conjecture be correct, these ancient Mammals belonged to the order of the Marsupials or Pouched Quadrupeds (Marsupialia), which are now exclusively confined to the Australian province, South America, and the southern portion of North America. In the Old World, the only known Triassic Mammals belong to the genus Microlestes, and to the probably identical Hypsiprymnopsis of Professor Boyd Dawkins. The teeth of Microlestes (fig. 157) were originally discovered by Plieninger in 1847 in the "bone-bed" which is characteristic of the summit of the Rhaetic series both in Britain and on the continent of Europe; and the known remains indicate two species. In Britain, teeth of Microlestes have been discovered by Mr Charles Moore in deposits of Upper Triassic age, filling a fissure in the Carboniferous limestone near Frome, in Somersetshire; and a molar tooth of Hypsiprymnopsis was found by Professor Boyd Dawkins in Rhaetic marls below the "bone-bed" at Watchet, also in Somersetshire. In North America, lastly, there has been found in strata of Triassic age one of the branches of the lower jaw of a small Mammal, which has been described under the name of Dromatherium sylvestre (fig. 156). The fossil exhibits ten small molars placed side by side, one canine, and three incisors, separated by small intervals, and it indicates a small insectivorous animal, probably most nearly related to the existing Myrmecobius.

LITERATURE.

The following list comprises a few of the more important sources of information as to the Triassic strata and their fossil contents:—

(1) 'Geology of Oxford and the Valley of the Thames.' Phillips. (2) 'Memoirs of the Geological Survey of Great Britain and Ireland.' (3) 'Report on the Geology of Londonderry,' &c. Portlock. (4) "On the Zone of Avicula contorta," &c.—'Quart. Journ. Geol. Soc.,' vol. xvi., 1860. Dr Thomas Wright. (5) "On the Zones of the Lower Lias and the Avicula contorta Zone"—'Quart. Journ. Geol. Soc.,' vol. xvii., 1861. Charles Moore. (6) "On Abnormal Conditions of Secondary Deposits," &c.—'Quart. Journ. Geol. Soc.,' vol. xxiii., 1876-77. Charles Moore. (7) 'Geognostische Beschreibung des Bayerischen Alpengebirges.' Guembel. (8) 'Lethaea Rossica.' Pander. (9) 'Lethaea Geognostica.' Bronn. (10) 'Petrefacta Germaniae.' Goldfuss. (11) 'Petrefaktenkunde.' Quenstedt. (12) 'Monograph of the Fossil Estheriae' (Palaeontographical Society). Rupert Jones. (13) "Fossil Remains of Three Distinct Saurian Animals, recently discovered in the Magnesian Conglomerate near Bristol"—'Trans. Geol. Soc.,' ser. 2, vol. v., 1840. Riley and Stutchbury. (14) 'Die Saurier des Muschekalkes.' Von Meyer. (15) 'Beitraege zur Palaeontologie Wuerttembergs.' Von Meyer and Plieninger. (16) 'Manual of Palaeontology.' Owen. (17) 'Odontography:' Owen. (18) 'Report on Fossil Reptiles' (British Association, 1841). Owen. (19) "On Dicynodon"—'Trans. Geol. Soc.,' vol. iii., 1845. Owen. (20) 'Descriptive Catalogue of Fossil Reptilia and Fishes in the Museum of the Royal College of Surgeons, England.' Owen. (21) "On Species of Labyrinthodon from Warwickshire"—'Trans. Geol. Soc.,' ser. 2, vol. vi. Owen. (22) "On a Carnivorous Reptile" (Cynodraco major), &c.—'Quart. Journ. Geol. Soc.,' vol. xxxii., 1876. Owen. (23) "On Evidences of Theriodonts in Permian Deposits," &c.—'Quart. Journ. Geol. Soc.,' vol. xxxii., 1876. Owen. (24) "On the Stagonolepis Robertsoni," &c.—'Quart. Journ. Geol. Soc.,' vol. xv., 1859. Huxley. (25) "On a New Specimen of Telerpeton Elginense"—'Quart. Journ. Geol. Soc.,' vol. xxiii., 1866. Huxley. (26) "On Hyperodapedon"—'Quart. Journ. Geol. Soc.,' vol. xxv., 1869. Huxley. (27) "On the Affinities between the Deinosaurian Reptiles and Birds"—'Quart. Journ. Geol. Soc.,' vol. xxvi., 1870. Huxley. (28) "On the Classification of the Deinosauria," &c.—'Quart. Journ. Geol. Soc.,' vol. xxvi., 1870. Huxley. (29) "Palaeontologica Indica"—'Memoirs of the Geol. Survey of India.' (30) "On the Geological Position and Geographical Distribution of the Dolomitic Conglomerate of the Bristol Area"—'Quart. Journ. Geol. Soc.,' vol. xxvi., 1870. R. Etheridge, sen. (31) "Remains of Labyrinthodonta from the Keuper Sandstone of Warwick"—'Quart. Journ. Geol. Soc.,' vol. xxx., 1874 Miall. (32) 'Manual of Geology.' Dana. (33) 'Synopsis of Extinct Batrachia and Reptilia of North America.' Cope. (34) 'Fossil Footmarks.' Hitchcock. (35) 'Ichnology of New England.' Hitchcock. (36) 'Traite de Paleontologie Vegetale.' Schimper. (37) 'Histoire des Vegetaux Fossiles.' Brongniart. (38) 'Monographie der Fossilen Coniferen.' Goeppert.