in the alluvial deposits: a further fact of vast importance is, that the majority of the fossil remains associable with the Rosares are the remains of recent genera, very few relics of extinct species being found. And, as will be anticipated from the results of similar investigations into the relative distribution and affinities of fossils belonging to the other classes, those remains which are similar to plants at present in existence, are found in the superior or later formations, while those which, although exhibiting a relationship to recent vegetables, are specifically or generically different from any now known to be in existence, are met with in the lower or under strata.

(4880.) Of the vegetable exuviæ found in the soil, and among the detritus forming beds in the present day, nothing need be said. They, of course, are the remains of existing species, and are met with in a more or less decayed, or in a more or less preserved, condition, according to the character of the deposits in which they lie, whether in sand-banks, morasses, peat-bogs, &c. But the submarine forests, which are so continually cropping out on the sea-coasts, are most peculiarly interesting. They consist of multitudes of fragments, chiefly of dicotyledonous trees, many of which are recognizable, such as oak, elm, birch, poplar, willow, hazel, &c.; and the leaves as well as fruit of several are also found along with their woody trunks and branches, such especially as vast quantities of nuts. One of these submarine forests, on the coast of Lincolnshire, has been well described by Correa de Serra. He says it was "composed of the roots, trunks, branches, and leaves of trees and shrubs, intermixed with aquatic plants, many of the roots still standing in the position in which they grew, while the trunks were laid prostrate. Birch, fir, and oak, were distinguishable, while other trees could not be determined. In general, the wood was decayed and compressed, but sound pieces were occasionally met with, and employed for economical purposes by the people of the country. The subsoil is clay, above which were several inches of compressed leaves, and among them some considered to be those of the (common holly) Ilex Aquifolium." Many similar deposits have been found, not only on the sea-coast, but inland, such as in Hatfield-bog, in Yorkshire; and the Lincolnshiremoor, as Correa terms it, is considered to extend at least from Peterborongh to Sutton, which places are sixty miles apart. De la Beche has collected records from various sources of a great number of such deposits which have been discovered in all parts of these islands, from the Orkneys and Hebrides to Cornwall, as well as in numerous other parts of Europe, as on the shores of the Baltic, the coasts of Normandy, and so forth. That on the Frith of Tay is described, by Dr. Fleming, to consist" of the remains of leaves, stems, and roots, of many common plants of the natural orders Equisetaceæ, Gramineæ, and Cyperaceæ, mixed with the roots, leaves, and branches of birch, hazel, and probably also alder. Hazelnuts destitute of kernel are of constant occurrence." Of another submarine forest, at Largo Bay, Dr. F. says, "the peat is composed of land and fresh water plants, among which are the remains of birch, hazel, and alder trees; hazel-nuts are also seen, and the root of one tree, apparently an alder, was traced more than six feet from the trunk."

In Tiree, one of the Hebrides, a submarine forest has been described by the Rev. C. Smith, in which, "besides the remains of trees. which are obvious, there are other and smaller plants, and numerous seeds which at first looked quite fresh, but afterwards became darker on exposure to the air. These seeds are said to have the appearance of belonging to some leguminous plant; and Mr.

Drummond suggests that they may probably be those of Genista Anglica. Another such bed has been found in Mount's-bay, Cornwall; and Dr. Boase says it consists of a brown mass composed of the bark, twigs, and leaves of trees, which appear to be almost entirely hazel. In this there are numerous branches and trunks of trees. The greater part of this wood is hazel, mixed with alder, elm, and oak. About a foot below the surface of this bed the chief part of the mass is composed of leaves, amongst which hazel-nuts are very abundant. Similar and other remains have been found in other places, and in some, as De la Beche continues, "the Arundo Phragmites so abounds, that the peaty moss seems entirely composed of it. The lower layers contain Ceratophyllum demersum. Potamogeton pusillum, Najas major, Nymphæa lutea, Scirpus palustris, and Hippuris vulgaris, are also discovered with the Arundo. Seeds, especially of the Menyanthes trifoliata, are likewise frequent in the lower layers."

(4881.) The similitude of the vegetable exuviæ in these recent beds with species now existing, is an important fact; but a fact of still greater importance is, their identity with the plants now growing on the surface of the earth in the countries where they are found. For, if organic remains deposited in beds now forming, or which have been formed during the present epoch, be similar to those now growing on the surface, there can be no reason to doubt that the fossil remains discovered in the older strata were similar to those then growing on the surface during the period in which they were laid up. If in the peat-bogs and submarine forests of the superior beds the only remains to be met with are those of native plants, and none are discovered belonging to distant regions, and which must have been conveyed from the present torrid to the temperate, or the frigid zones, the probability is great, if the conclusion be not wholly unavoidable, that, in the inferior strata, the fossils met with are those of vegetables which were then proper to the surface of the globe, in the latitudes in which they occur.

(4882.) Numerous other examples might be given of vegetable remains occurring in similar situations, but this would be a work of supererogation; therefore, let it suffice to observe, that throughout the upper fresh-water formation the remains are without exception those belonging to plants of our present existing flora. In the lower beds of the tertiary series, although the relics of recent plants are those which are the most abundant, peculiarities gradually occur; first, as in the lower fresh-water formation, vestiges of tropical species, such as some Sterculiæ, Cecropiæ, and arborescent Malvaceæ, are found; and in the London clay tropical fruits, of perhaps extinct species, abound in a fossil state: e. g. in one confined locality, viz. the Isle of Sheppy, "Mr. Crowe, of Faversham, has made a collection of seed-vessels, amounting to no less than 700 different varieties, of which very few agree with any existing seed-vessels known to botanists." (Ure.) Thus, even during the passage downwards through the tertiary beds alone, a most decided difference is observed in the characters of the fossils. For, taking Britain as an example, in the upper deposits there are discoverable nothing but the remains of British plants; while in the lower the fossils are those of vegetables now peculiar to the tropics, or to much warmer climates, than prevail in these latitudes in the present day.

(4883.) Besides the oak, the elm, the hazel, the chesnut, the birch, the alder, the poplar, and the willow, which occur so frequently in all the supercretaceous beds that they can scarcely be said to be proper to any one, although certainly most prevalent in the upper, there have been discovered a few fossils that have a more

limited range; thus, one of the Nympha acea, Nymphea Arethusa, or probably Nuphar lutea, is found in the upper fresh-water formation. One species of Betula, B. Dryadum; one of Carpinus, C. macroptera; one of Comptonia, C. acutiloba, are met with in the lignite of the tertiary beds. And another species of Comptonia, C. Dryandrefolia, is peculiar to the lower fresh-water formation. The three or four species of walnuts known in a fossil state are said by Brongniart to be Juglans Nux Taurensis, proper to the upper marine deposit; J. ventricosa and J. laevigata to the lignites of the tertiary beds; and J. Salinarum to the marine formation of Wieluzka. Besides these, one species of Laurus, the Cinnamomum, is said to have been recognized in the fresh-water deposits, at Aix, where there have likewise been found the leaves of some leguminous plants, the generic affinities of which cannot be traced, and to which the name Phaseolites has been given.

(4884.) In the true secondary or supermedial strata, that is, in all the beds above the carboniferous, and below the supercretaceous series, the remains of plants belonging to this class are very rare. In the chalk and in the Jura, the shelly and the magnesian limestone, none have been found; and a solitary species of walnut is alone mentioned as having been discovered in the upper bed of new red sandstone.

(4885.) A remarkable change, however, occurs in the carboniferous series, for с

B

a

c. Asterophyllites

foliosa. c, a. Ditto galioides. D. Cardiocarpon acutum. (a) Ditto natural size. E. Sigillaria pachyderma. (a) Fragment of one of the branching roots. (b) Part of the decorticated stem.

[From Lindley and Hutton's Fossil Flora.]

there among ferns and palms, and pines, among the earlier and richer vegetations of the world, the Rosares, or at least some representatives of them, are met with

in profusion; and, though the extent may be almost inconceivable to those who have not personally examined the beds, to all who have seen them, the incredible abundance in which they are found may be taken as evidence of their prevalence in the coal epoch: as their exceeding size is a proof of their luxuriant growth. These fossils, which are familiar to all who have ever examined, or who have even entered a coal-mine, are the Cactites and Euphorbites of Sternberg, Artis, and others. Adolphe Brongniart, who doubts their relationship to the modern Cacti and Euphorbia, has called them Sigillaria and Stigmaria. As these latter names do not implicate any questioned proposition, they are perhaps the preferable ones; and the more especially as, although, from recent researches and observations, the opinions of Sternberg and Artis are in part confirmed, viz. as to their being the remains of succulent exogenous or dicotyledonous vegetables, possessed of distinct bark, wood, and pitch, but in which the parenchyma was greatly developed; still their immediate affinity to either of our modern succulent groups, such as the Mesembracea, Crassulaceæ, Stapeliacea, Euphorbiacea, and Nopalacea, cannot be said to be definitively determined. That their relationship to the latter two is by far the strongest there is no doubt; yet, as neither leaves, flowers, nor fruit, have been hitherto discovered, it is better not to assume a closer connexion than subsequent experience may be enabled to confirm.

(4886.) Von Martius, who enjoyed excellent opportunities of observing the habits and varied forms of Cacti in their most luxuriant states of modern growth, in Brazil, and the other parts of tropical America, appears to be strongly impressed with the close similitude observable between these fossils and recent Cacti ; and he even attempts to trace the resemblance of the different fossil remains to several existing species, as to Cactus tetragonus, pentagonus, hexagonus, &c. While his Cactites tessellatus, he thinks rather to belong to the subgenus Opuntia than to the genuine Cacti. Lindley and Hutton, however, seem to incline to the opinion of the nearer connexion of the Stigmaria to the Euphorbiacea, than to the Nopalacea, or rather, to some intermediate type that is now extinct.

(4887.) Besides the above, there are many other vegetable remains which appear to approximate the exogenous series, but the affinities of which are at present not well made out. There are various unrecognized stems, leaves, flowers, and fruits, known under the collective names of Exogenites, Phyllites (?) Antholites ( ? ) and Carpolithes; some of which are indeed very questionable associates. These groups, which at present are for the most part heterogeneous and ill assorted, will hereafter be subdivided, so as to form more definite and satisfactory genera. Several generic groups have indeed already been separated from them, such as the Annularia, of which Brongniart mentions seven species as occurring in the coal measures, and some of these he thinks may belong to the genus Bechera; another species of which, B. grandis, he calls Asterophyllites dubia. Of the fossils named Asterophyllites 12 or 13 species have been distinguished; the whole of which, with a solitary exception, belong to the coal measures. This exception is however an important one, for A. pygmea is proper to the transition series. The affinities of the Asterophyllites, [§ 4885, c.] is very problematical. Brongniart suggests their resemblance to Hippuris, Myriophyllum, or Ceratophyllum, while the authors of the Fossil Flora of Great Britain hint at their similitude to some of the Rubiacea.

(4888.) The affinities of the so-called Phyllotheca, Calamites, [§ 4738, ], and

Volkmanniæ, have yet to be traced; further than that they have an exogenous tendency, and this less decided in the latter two than in the former, nothing can with safety be affirmed. The seeds, which have received the name of Cardiocarpa, are equally debateable as to their affinities; they are most probably the seeds of some dicotyledonous plant with an aggregate inflorescence, but whether they are the seeds of an Asterophyllites, or of some extinct genus of the Umbelliferæ, as suggested by Lindley and Hutton, it is impossible at present to determine.

(4889.) There is a very remarkable fossil, which Sternberg has included among his Lepidodendra, and called L. dichotomum, the L. Sternbergii of Brongniart; but Von Martius believes it to be the type of a new and distinct genus, which he proposes to name Lychnophorites, on account of its resemblance to the genus Lychnophora, which he discovered in the province of Minas Geraes, in Brazil, at the height of 2000 feet and upwards above the level of the sea, and especially in the diamond district. Of this newly discovered genus, which belongs to the natural order Asteriana or Composite, there are several species, such as Lychnophora Pinaster, rosmarinifolia, &c., forming shrubs about the height of a man. “They are much allied," he continues, "to the Vernonia of Linneus, and the Pullalesta of Humboldt, which seem to correspond in every particular with our petrified plant." And hence, if the conclusion of Martius be correct, there is found in the coal-seams of the North of England the relics of a plant allied to the tropical arborescent composite of the present day.

zone.

(4890.) Thus it appears that the correspondence of the geographical distribution with the geological position of the Rosares is, like that of the other classes, most decided. These plants, which are now so prevalent on the surface of the earth as to constitute emphatically the Flora of our epoch, are found in profusion in the upper strata of the globe: there, and there only, do they obtain any thing like the proportion to other fossils that they hold with relation to other recent plants. From the secondary strata they are all but absent; and, although they are found in profusion in the carboniferous rocks, they are only present by the relics of genera now extinct, and the nearest resemblances of which are our tropical Euphorbiacea and Nopalace, or to the arborescent Compositæ, peculiar now to equinoctial regions, and especially to insular situations within the torrid The extraordinary similitude, nay, almost absolute identity, of the organic remains of the superficial strata in European countries with their existing flora, is most worthy of remark; and, although the geological researches in other quarters of the globe do not as yet afford the means of ascertaining whether such a parallel exists every where, still, as in the alluvial deposits, and in the upper tertiary beds of northern latitudes, plants proper to the northern regions are found; so likewise it is more than probable, that when examinations are made, the remains of recent tropical plants will be found in the equivalent beds of the torrid zone. But what will be the probable character of the fossil remains of the equinoctial coal-beds? what plants will they resemble? and how great will their deviation be from any existing species?—seeing that the fossils of our carboniferous series appear to be the remains of vegetables, which enjoyed a climate hotter than that which now prevails beneath the line.