explained; since they possess (especially the roots of trees) that degree of solidity which appears to be favourable to the process of petrifaction. From the want of this necessary property it undoubtedly is, that we possess so few remains of tender flower leaves, and none of pulpy fruits.

From the same cause, the great prone. ness to decomposition, the number of animal fossils is considerably limited: those substances being only preserved in a mine. ralized state which originally possessed a considerable degree of solidity; such are the bones, teeth, horns, shells, scales, &c. The animal, however, far exceeds the vegetable kingdom in the number and variety of fossils which it yields, as well as in the distinctness of form, and excellency of preservation, in which they are found.

Adopting in a great measure the arrange ment of Waller, we shall commence our examination of the animal fossils with those which have derived their origin from corals. These fossils are, of course, merely the remains of the dwellings which have been formed by the various coral insects, and which are so frequently found in the cabinets of the curious.

Immediately on commencing this examination, we are struck with a similar want of agreement between the recent and fossil corals, with that which has been noticed between recent and fossil vegetables. Of the genus Tubipora it does not appear, at least by the observations made in Mr. Parkinson's second volume of "The Organic Remains of a former World," that a single species which is known recent has been found as a fossil. Several fossil species are, however, described, of which nothing similar is known in a recent state. The most striking of these is the Tubipora catenularia, or chain coral, the surface of which, in consequence of the tubes being in contact at their sides, has frequently a very curious reticulated or catenulated appearance. Plate I. fig. 4, represents this fossil in its usual state and at fig. 5 is shewn the appearance yielded by a transverse section. Tubipora fascicularis, T. stellata, T. repens, and T. strues, which have been described by different authors, and which are unlike to any known recent Tubipore, give reason for supposing that the number of species of fossil Tubipores exceeds that of the recent species.

The fossil Madrepores are not less rich in variety, nor less comparatively numerous, than the fossils of the preceding genus. The forms of several species of the fossil Madre

pores do frequently approach to those of the different recent species; but in a con. siderable number of the fossil Madrepores no resemblance is discoverable, except in their stelliform openings, with any recent coral. So great indeed is this departure in some instances from the general characters of our present known Madrepores, that it has been deemed difficult to determine, whether some fossil specimens should be considered as Madrepores or as Alcyonia. It is impossible, without the aid of numerous figures, to give satisfactory notions of the forms of the several fossil Madrepores which have been hitherto discovered; the most interesting only will therefore be here par. ticularized.

The Madrepores consisting of a single star appear to be much more numerous in a mineral than in a recent state. These are either of a discoidal form, having a concave superior and a convex inferior surface; of a pyramidal top-like form, terminating in a pedicle; or of a lengthened pyramidal form, bearing in some, from a slight curvature, the appearance of the horn of an animal; whilst others are cylindrical for a considerable part of their length.

The first of these, Madrepora porpita, the shirt-button Madrepore, has been long known to the collectors of fossils in this kingdom. Dr.Woodward describes several of them, as mycetitæ discoides. The second species (Madrepora turbinata) is also frequently found in different parts of Great Britain, as well as in Sweden, Norway, and in several parts of France, Switzerland, and Italy. These latter fossils have been termed by Dr. Woodward mycetitæ conoides seu calyciformes. When they have acquired somewhat of a hornlike shape, they have been distinguished by the term ceratites; and when they have possessed more of the cylindrical form, they have been termed columelli lapidei et hippurita; and from a supposed resemblance, they have been also considered as the petrified roots of briony. Some of the single starred corals are found united at their pedicle, and approaching towards each other at their summits, though disjoined nearly through their whole length. These, from their resemblance to petrified reeds, have been named junci lapidei.

It would be useless to attempt, in this sketch, to specify the considerable variety of fossil Madrepores formed of aggregated circular stars, and which have been designated as astroites, &c. Those which are composed of angulated stars are, perhaps, not so numerous: many of these, however,

are very different in their appearance from those which are known in a recent state. The one most known in these islands is the lithostrotion, sive basaltes striatus et stellatus, of Llwyd. The exact union of the sides of the polygons giving a tolerably correct idea of minute basaltes. The compound Madrepores, the stelliform part of which are extended in undulating labyrinthean forms, appear to be much less numerous as fossils than any of the other corals: their existence in a silicious state very rarely occurs.

The Millepora do not appear to be nearly so frequently found in a mineral as in a recent state. Several fossils have been placed among the Millepores which undoubtedly should rank with the Madre pores: such are the Millepora simplex turbinata, and the Millepora simplex discoides, of Waller and Gesner; a careful examination shewing, that these differ from the porpital and turbinated Madrepores, only in their being formed of numerous tubes, possessing an internal stellated structure.

Of the genus Isis one species only appears to be known as a fossil. This species was first described by Scilla, who at first conjectured it to be the leg bone of some ani. mal. Specimens are frequently found in the Calabrian mountains, and have lately been also found in some parts of Wiltshire. Of the genus Cellepora, Antipathes, and Gorgonia, fossil specimens appear to be rather

uncommon.

The Corallo Fungitæ of Waller are evidently the fossil remains of Alcyonia. These have been long described by Volkmann, Scheuchzer, and others, as fossil fruits, and have obtained, from their resemblance to figs, &c. the appellations of ficoides, caricoides, &c.; whilst others of a different form have been named lycoperditæ, fungitæ pilcati, &c. A fossil Alcyonium has even been described by Volkmann and Scheuchzer as a fossil nutmeg. A fossil Alcyonium of a conical form is represented Plate I. fig. 6.

The Encrini and Pentacrini have been always, and very properly, considered as the most curious of the fossil Zoophytes. The Encrinus (Plate I. fig. 3) possesses the distinguishing character of having its spine, or, as it has been generally called, its tail, composed of cylindrical or orbicular vertebræ, pierced through their centre, and marked with diverging striæ on their articulating surfaces. On the superior termination of these is placed the base of the

body of the animal, formed of five trapezoidal bodies, termed by Rosinus articuli trapezoides, which inclose five small bodies, which form the centre of the base; the whole of these forming that which Rosinus denominated the pentagonal base. From each of these proceed six other bodies, on the two last of each series of which are placed the arms of the animal, which divide into fingers; from the internal surface of these proceed almost innumerable articulated tentacula. This fossil has long possessed the name of the Encrinus, or stone lily; its resemblance to that flower having led to the suspicion that it was a petrifaction of a flower, approximating in its form to the lily: its animal origin is however now completely ascertained. Indeed, if a doubt had remained, it would have been removed by the circumstance of the animal membrane, or cartilage, having been actually discovered in the fossil, (“Organic Remains of a former World," vol. ii. p. 166.) Several other species of this animal are also described in the work just referred to; but hitherto no recent animal has been found which can be referred to this genus.

The fossil Pentacrinus differs from the Encrinus, in its vertebra being of a pentagonal form, and in its arms, fingers, and tentacula being capable of being much more widely spread and extended than are those of the Encrinus. It appears from Mr. Parkinson's account, that there are several species of this fossil, the existence of some recent species of which have been also ascertained.

The encrinital vertebræ (Plate I. fig. 7 a) have been hitherto termed trochita when separate, and entrochi when connected in a series, (Plate I. fig. 7.) The single vertebræ of the Pentacrinus have been distinguished as asteriæ, (Plate I. fig. 8 a); and when united together they have been termed columnar asteria, (Plate I. fig. 8.)

Of the Asteriæ, or Stellæ Marinæ, some very few specimens have been found fossil; but they occur very rarely, and have, in general, been found in a condition too imperfect to allow of any positive opinion being formed, respecting the species to which they belong.

The fossil Echini are very numerous, upwards of forty species, known only as fossils, being enumerated by the illustrions Linnæus; to delineate, therefore, even those most deserving of notice could not be here well accomplished; a circumstance, however, which is not so much to be regretted,

since, though materially different, they approach very nearly in their general form to the recent species. Those which possess a hemispherical, or a nearly orbicular form, with large mamilla-like protuberances, and the anus disposed vertically, have been distinguished as the turban echini (echini cidares); those which resemble a shield or buckler in their figure are termed the shield echini (clypei Kleinii); and one of the largest of these has been named the polar stone by Dr. Plot (Plot's Oxfordshire, p. 91.) When of a depressed circular form, with the anus in the edge of the inferior part, they are the fibulæ of Klein; of a conical form, the eaglestone of the Germans (conuli, Kleinii); with a circular base, the quoit echinus (discoidei, Kleinii). When the base is an acute oval, the mouth and anus being at the opposite ends, they are termed the helmet echinis, (cassides et galeæ, Kleinii); and when heart-shaped, with a sulcated superior surface, they are called snake's hearts (spatangi, Kleinii.)

The attempt to particularize the various species of fossil shells which have been found would require a large volume: all that can be here done is to notice some of those which totally differ from any which exist in a recent state, and to offer some few remarks on those which approximate, or are perhaps similar to some of the species which are known in a recent state.

With respect to the state in which fossil shells are found, it is necessary to remark, that, in some situations, shells which have been buried for ages, by the natural changes which the surface of the earth has undergone, are found very little changed, except from the loss of colour, and having been rendered extremely fragile; that in other situations the substance of the shell has been so injured, as to be reduced to very small fragments, and even to a fiue powder, leaving in some instances a stony, correctly moulded, cast of the cavity of the shell; that very frequently the substance of the shell is entirely altered, having become a calcareous stone, or a silicious or pyritous mass, and that the shells of a former world are frequently found in masses of marble, which is called lumachelli, or shelly marble.

Of the Multivalves, the chiton does not appear to have been found in a mineralized state; and although several species of Lepas have been found in a mineral state, they are by no means frequent fossils. Lepas anserifera is said to have been found fossil,

as well as Lepas diadema; these must, however, be exceedingly rare fossils.

Fossil shells of the Pholas are by no means common; the Pholas crispata has been however, found among the Harwich fossils.

Fossil bivalves are very common fossils; they are, as might be expected, very sel dom found in pairs, except when united by a lapideous mass, which prevents the examination of their hinge, or their internal structure, which in many fossil shells, are objects highly worthy of examination.

The Mya pictorum is described by Solander as existing among our Hampshire fossils: a fossil mya of three or four inches in length, is found also in the rocks near Bognor. Remains of the solen siliqua, and of the solen ensis, have been found at Harwich, and a small fossil shell, named by Solander solen ficus, has been found between Lymington and Christchurch.

Fossil shells of the genus Tellina, as well as of cardium, mactra, donax, venus, spondylus, chama, arca, and particularly ostrea, have been found of many species But no bivalve exists as a fossil in such prodigious numbers, and in such various species, as those of the genus Anomia. These shells are characterized by the beak of the largest or under valve, which is perforated, being greatly produced, rising or curving over the beak of the smaller or upper valve. Anomia lacunosa (Plate II. fig. 1.) is one of the most abundant of these species. They are found in considerable quantities in different parts of England, particularly in Lincolnshire, Warwickshire, and Gloucestershire. Anomia terebratula, (Plate II. fig. 2), is another fossil of this genus, which exists in different counties in this island, in great abundance.

Of the genus Mytilus several species are known as fossils, some of which approach very near to those which are known recent : one in particular appears to differ very little indeed from Mytilus modiolus. Fossil shells of the genus Pinna, in any tolerable state of preservation, are not frequently found: the shells are in general so fragile as to render it very difficult to obtain them tolerably perfect; or so that but little information can be yielded respecting the species to which they belong.

No fossil shell appears yet to have been found which can with certainty be placed under the genus Argonauta. But of the genus Nautilus, specimens are very frequent. These have been found in several parts of

this island: some very fine specimens have been found at Lime in Dorsetshire, in different parts of Wiltshire, and at Whitby in Yorkshire. The finest specimens are perhaps found in the neighbourhood of Bath, and in the Isle of Sheppey in Kent, at which latter place they are found exceed ingly large, and still retaining a resplendent pearly shell. (Plate II. fig. 3.)

The Cornu Ammonis, which, if we except the extremely minute shells of this kind which have been seen by Plancus, and others, in the sea sand on the Venetian shores, may be said to be only known to us in a fossil state.

Like the Nautilus, the Cornu Ammonis is divided into compartments, by regularly disposed partitions, and these partitions are perforated, as are those of the Nautilus, although it is by no means easy to point this out, except in very few specimens.

There are none of the fossil shells, except perhaps the Anomiæ, which can vie in the variety of their species with the Cornu Ammonis. The shell of some is perfectly smooth over its whole surface; in others smooth at the sides, but ridged or beset with spines at the back; and others, though smooth at the side, are crenulated at the back. The species most commonly met with have the shell variously ridged; some with small close striæ, and others with large and round ridges. In some the ridges are single, in others bifurcated, and in others trifurcated. In some, and these are least common, the shell is tuberculated: these tuberculæ differing considerably in different species, in their size, form, and disposition. The different species proceeding from the intermixture of all these varieties, it must be obvious, must be exceedingly numerous : Schenchzer was able to determine the existence of one hundred and forty-nine species. The difference of size observable in these fossils is not less remarkable than the variety of their forms, some being found not much larger than the head of a pin, whilst others have been found as large as the top of a small table.

A peculiar appearance is observable on the surface of many of these fossils, which depends on the peculiar form of the septa which separate the chambers of the shell. These septa in the nautili are smooth, and terminate at the surface of the shell in a straight line; but in the Cornua Ammonis they become undulated as they extend outwardly; and in some so much so as to form, on the outer surface, deeply crenulated

lines, giving the appearance of foliaceous sutures. When the cavities of the shell have become filled with stone, and the septa just mentioned have been removed, as is frequently the case, by some chemical agent, the casts formed in the chambers separate, each forming a curiously figured stone; these separate casts have been termed spondylolites. (Plate II. fig. 4.) By the junction of these are formed the foliaceous sutures above mentioned. The Cornua Ammonia were formerly called serpentstones; the appearance which they yield of a serpent coiled having led the vulgar to consider them as petrified serpents.

The fossil Cones are very few when compared with the numerous species known in a recent state; the same may be also said of the Cyprææ. In both these genera the species are mostly made out more from the colour and the markings of the shells, than from the peculiarities of their form; but in the fossil shells the colours no longer exist, and of course the species in these can very seldom be presumed. The fossil Volutes, as far as can be judged from their form alone, differ generally from the recent species. With respect to the genus Buccinum, Strombus, and Murex, the number of species of the fossil shells do not appear to equal those which are known in a recent state. This is the case also, in a still greater degree, with the genus Trochus. The fossil shells of the genus Turbo are pretty numerous, and some of them very closely resemble those of known recent species. One fossil shell of this genus is very remarkable for its vast size, being upwards of a foot in length. The cast of another species is so large as to weigh four or five pounds. Nothing like this occurs with respect to the species of the genus Helix: the fossil shells of this genus very much resemble those which are recent, and are not found of any considerable magnitude. The fossil shells of the genus Nerita by no means display so many species as the recent; but some of the fossil species far exceed the recent in size, and one in particular is twelve times the size of any known recent species. Of the genus Haliotis, it is not positively determined that a single shell has been seen, which could be considered as fossil. Fossil shells of the genus Patelta are by no means common. Several species have, however, been found in France, in a state of excellent preservation. Some few also have been found in the cliffs at Harwich, and others, of a different species,

imbedded in the lime-stone of Gloucestershire. Dentalia, apparently similar to existing species, have been found in Hampshire, and in some parts of France and Italy, exceedingly well preserved. In Italy also have been found specimens of Serpulæ, very similar to those which are known recent; but others have been found in France exceedingly different from any known re. cent species.

The Orthoceratites, a lapidified conical or cylindrical chambered shell, the septa dividing the chambers of which are perforated like those of the Nautilus, is a genus of which not a species is known in a recent state, excepting the microscopic specimens found by Plancus in the sand of the Riminian shore. Much is wanting to complete the history of this fossil, since from the state in which the specimens have in general been found, very few, or perhaps none, have been obtained perfect. Authors have divided them into those which are straight (Plate II. fig. 8.), and those which have a spiral termination, the latter of which are considered as fossil shells of the Nautilus lituns; but the extraordinary disparity of size is sufficient to shew that they can hardly be considered of the same species, the recent shell being seldom more than an inch in length, whilst the fossil is described as being sometimes the size of a man's arm.

The Belemnite (Plate II. fig. 7.) is a spathose radiated stone, generally conical, but sometimes possessing a fusiform figure, and contains, in an appropriate cavity at its larger eud, a smaller calcareous body (alveo lus) which has evidently been a concamerated shell, the septæ of which are pierced like those of the preceding fossil. These fossils are from an eighth of an inch to two inches in thickness, and from an inch to a foot and a half in length. They are some times found imbedded in chalk or limestone, and sometimes in pieces of flint; but they are most frequently detached from their matrix. Various have been the opinions respecting this fossil; some have considered it as the horn of a narwhal, and others as a concretion formed in the pennicilla marina, or in some shell of the dentalium kind. Some have even supposed it to be of vegetable origin, whilst others have considered it as entirely belonging to the mineral kingdom. But that the Belemnite originally existed in the sea, is evident from its being commonly found with the remains of the undoubted inhabitants of the ocean, and that it is of an animal nature, is reu

dered evident by its structure. Among the concamerated fossil shells may be placed the Helicites, or nummular, or lenticular stones. These are round flattish bodies; but in general of a lenticular form, both sides possessing a slight degree of convexity. On each side are sometimes seen traces of its internal structure and of its spiral formation; whilst sometimes these appearances appear to be concealed by a thicker covering. Various opinions have been entertained respecting their origin, but no doubt can exist of their having existed in the ancient ocean as a spiral chambered shell, and of their being one of those species of animals which are now lost.

Among the fossil shells which can only be here enumerated, are the rare tuberculated turrilite, or chambered turbinated shell, the orbulites, planulites, and baculites of Lamarck.

Insects of the smaller kinds are seldom found in a fossil state, the smallness of their size and the delicacy of their structure most probably preventing their preservation. Those which are in a state to allow any thing of their general form to be made out are consequently very few. The one which is generally found in the most perfect condition, is that which is generally known to us as the Dudley fossil, from its being found in the neighbourhood of Dudley, in Worcestershire. (Plate II. fig. 5.) Other species of this animal have been found in Wales, and in different parts of Germany. From the imperfect state in which these insects are found, little more, perhaps, can be said of them, except that the remains which have been examined shew that the covering of their body was formed by three series of thick crustaceous plates, transversely disposed in rows, the length of the body; whilst one plate served to give a covering to the head of the animal. Other remains of the smaller insects have been mentioned by different authors; but few or none appear to have been described as agreeing with any insect now known to be in existence.

The remains of lobsters, and crabs, are frequently found in the isle of Sheppey, and Malta. The remains of different species of these animals are also found in a compressed state in the margaceons and schistous masses of Pappenheim and Oppenheim.

The fossil remains of amphibia are very numerous, and supply us with ample exercise for inquiry and admiration. In different parts of England, particularly in