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This third great change in the vegetable kingdom is considered to supply another argument in favour of the opinion, that the temperature of the Atmosphere, has gone on continually diminishing from the first commencement of life upon our globe.

The number of species of plants in the various divisions of the Tertiary strata, is as yet imperfectly known. In 1828, M. Ad. Brongniart considered the number then discovered, but not all described, to be 166. Many of these belonging to Genera at that time not determined. The most striking difference between the vegetables of this and of the preceding periods is the abundance in the Tetiary series, of existing forms of Dicotyledonous Plants and large trees, e. g. Poplars, Willows, Elms, Chestnuts, Sycamores, and many other Genera whose living species are familiar

to us.

Some of the most remarkable accumulations of this vegetation are those, which form extensive beds of Lignite and Brown-coal.* In some parts of Germany this Brown-coal occurs in strata of more than thirty feet in thickness, chiefly composed of trees which have been drifted, apparently by fresh-water, from their place of growth, and spread forth in beds, usually alternating with sand and clay, at the bottom of then existing lakes or estuaries.

The Lignite, or beds of imperfect and stinking Coal near Poole in Dorset, Bovey in Devon, and Soissons in France, have been referred to the first, or Eocene period of the Tertiary formations. To the same period probably belongs the Surturbrand of Iceland, (see Henderson's Iceland, vol. ii. p. 114.) and the well-known examples of Brown-coal on the Rhine near Cologne and Bonn, and of the Miesner mountain, and Habichtswald near Cassel. These formations occasionally contain the remains of Palms, and Professor Lindley has lately recognised, among some speci

* See an admirable article on Lignites by Alexandre Brongniart in the 26th vol. of the Dictionnaire des Sciences Naturelles.

mens found by Mr. Horner in the Brown-coal near Bonn (See Ann. Phil. Lond. Sept. 1833, V. 3, 222,) leaves closely allied to the Cinnamomum of our modern tropics, and to the Podocarpus of the southern hemisphere.*

In the Molasse of Switzerland, there are many similar deposites affording sometimes Coal of considerable purity formed during the second, or Miocene period of this series, and usually containing fresh-water shells. Such are the Lignites of Vernier near Geneva, of Paudex and Moudon near Lausanne, of St. Saphorin near Vevay, of Kæpfnach near Horgen on the lake of Zurich, and of Eningen near Constance.

The Brown-coal at Eningen forms thin beds of little

* At Pützberg near Bonn, six or seven beds of Brown-coal alternate with beds of sandy clay and plastic clay. The trees in the Brown-coal are not all parallel to the planes of the strata, but cross one another in all directions, like the drifted trees now accumulated in the alluvial plains, and Delta of the Mississippi; (see Lyell's Geology, 3d. edit. vol. i. p. 272.) some of them are occasionally forced even into a vertical position. In one vertical tree at Pützberg, which was three yards in diameter, M. Nöggerath counted 792 concentric rings. In these rings we have a chronometer, which registers the lapse of nearly eight centuries, in that early portion of the Tertiary period which gave birth to the forests, that supplied materials for the forma tion of the Brown-coal.

The fact mentioned by Faujas that neither roots, branches, or leaves are found attached to the trunks of trees in the Lignite at Bruhl and Liblar near Cologne, seems to show that these trees did not grow on the spot, and that their more perishable parts have been lost during their transport from a distance.

In the Brown-coal Formation near Bonn, and also with the Surturbrand of Iceland, are found Beds that divide into Laminæ as thin as paper (Papier Kohle) and are composed entirely of a congeries of many kinds of leaves. Henderson mentions the leaves of two species of Poplar, resembling the P、 tremula and P. balsamifera, and a Pine, resembling the Pinus abies as occurring in the Surturbrand of Iceland.

Although we have followed Brongniart in referring the deposites here enumerated to the first or Eocene period of the Tertiary series, it is not improbable that some of them may be the products of a latter era, in the Miocene or Pliocene periods. Future observations on the Species of their animal and vegetable remains will decide the exact place of each, in the grand Series of the Tertiary formations.

importance for fuel, but very perfect remains of vegetables are dispersed in great abundance through the marly slates and limestone quarries which are worked there, and afford the most perfect history of the vegetation of the Miocene Period, which has yet come within our reach.*

* I have recently been favoured by Professor Braun of Carlsruhe, with the following important and hitherto unpublished catalogue, and observations on the fossil plants found in the Fresh-water formation of ŒŒningen, which has been already spoken of in our account of fossil fishes. The plants enumerated in this catalogue, were collected during a long series of years by the inmates of a monastery near Eningen, on the dissolution of which they were removed to their present place in the Museum of Carlsruhe. It appears by this catalogue that the plants of Eningen afford examples of thirty-six species belonging to twenty-five genera of the following families.

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This table shows the great preponderance of Dicotyledonous plants in the Flora of Eningen, and affords a standard of comparison with those of the Brown-coal of other localities in the Tertiary series. The greater number of the species found here correspond with those in the Brown-coal of the Wetteraw and vicinity of Bonn.

Amid this predominance of Doctyledonous vegetables, not a single herbaceous plant has yet been found excepting some fragments of Ferns and Grasses, and many remains of aquatic plants: all the rest belong to Dicotyledonous, and Gymnospermous ligneous plants.

Among these remains are many single leaves, apparently dropped in

No distinct catalogues of plants found in the Pliocen or most recent periods of the Tertiary series, have yet bee published.

the natural course of vegetation; there are also branches with leaves o them, such as may have been torn from trees by stormy weather; ripe see vessels; and the persistent calix of many blossoms.

The greater part of the fossil plants at Eningen (about two-thirds) b long to Genera which still grow in that neighbourhood; but their speci differ, and correspond more nearly with those now living in North Americ than with any European species, the fossil Poplars afford an example of th kind.

On the other hand, there are some Genera, which do not exist in the pr sent Flora of Germany, e. g. the Genus Diospyros; and others not in the of Europe, e. g. Taxodium, Liquidambar, Juglans, Gleditschia.

Judging from the proportions in which their remains occur, Poplars, Wi lows, and Maples were the predominating foliaceous trees in the form Flora of Eningen. Of two very abundant fossil species, one, (Populu latior,) resembles the modern Canada Poplar; the other, (Populus ovali resembles the Balsam Poplar of North America.

The determination of the species of fossil Willows is more difficult. On of these (Salix angustifolia) may have resembled our present Salix viminali Of the genus Acer, one species may be compared with Acer campestr another with Acer pseudoplatanus; but the most frequent species, (Ac protensum,) appears to correspond most nearly with the Acer dasycarpon North America; to another species, related to Acer negundo, Mr. Brau gives the name of Acer trifoliatum. A fossil species of Liquidambar (1 europeum, Braun.) differs from the living Liquidambar styracifluum America, in having the narrower lobes of its leaf terminated by longe points, and was the former representative of this genus in Europe. Th fruit of this Liqeidambar is preserved, and also that of two species of Ac and one Salix.

The fossil Linden Tree of Eningen resembled our modern large leave Linden tree (Tilia grandiflora.)

The fossil Elm resembled a small leaved form of Ulmus campestris.

Of two species of Juglans, one (J. falcifolia) may be compared with th American J. nigra; the other, with J. Alba, and like it, probably belonge to the division of nuts with bursting external shells, (Garya Nuttal.)

Among the scarcer plants at Eningen, is a species of Diospyros (D. bra chysepala.) A remarkable calyx of this plant is preserved, and shows i its centre the place where the fruit separated itself: it is distinguished from the living Diospyros lotus of the South of Europe by blunter and shorter se tions.

PALMSIN SECONDARY AND TRANSITION SERIES.

385

Fossil Palms.

The discovery of the remains of Palms Trees in the Brown-coal of Germany has been already noticed; and the

Among the fossil shrubs are two species of Rhamnus; one of these (R. multinervis, Braun) resembles the R. alpinus, in the costation of its leaf. The second and most frequent species, (R. terminalis, Braun) may with regard to the position and costation of its leaves, be compared in some degree with R. catharticus, but differed from all living species in having its flowers placed at the tips of the plant.

Among the fossil Leguminous plants is a leaf more like that of a fruticose Cytisus than of any herbaceous Trefoil.

Of a Gleditschia, (G. podocarpa, Braun) there are fossil pinnated leaves and many pods; the latter seem, like the G. Monasperma of North America, to have been single seeded, and are small and short, with a long stalk con. tracting the base of the pod.

With these numerous species of foliaceous woods, are found also a few species of Coniferæ. One species of Abies is still undertermined; branches and small cones of another tree of this family (Taxodium europeum, Ad. Brong.) resemble the Cypress of Japan (Taxodium Japonicum.)

Among the remains of aquatic plants are a narrow-leaved Potamogeton; and an Isoetes, similar to the I. lacustris now found in small lakes of the Black Forest, but not in the Lake of Constance.

The existence of Grasses at the period when this formation was deposited, is shown by a well preserved impression of a leaf, similar to that of a Triticum, turning to the right, and on which the costation is plainly expressed.

Fragments of fossil Ferns occur here, having a resemblance to Pteris aquilina and Aspidium Filix mas.

The remains of Equisetum indicate a species resembling E. palustre. Among the few undetermined remains are the five-cleft and beautiful veined impressions of the Calyx of a blossom, which are by no means rare at Eningen.

No remains of any Rosacea have yet been discovered at this place." Letter from Prof. Braun to Dr. Buckland, Nov. 25, 1825.

In addition to these fossil Plants, the strata at Eningen contain many species of fresh-water Shells, and a remarkable collection of fossil Fishes which we have before mentioned, P. 285. In the family of Reptiles they present a very curious Tortoise, and a gigantic aquatic Salamander, more than three feet long, the Homo Diluvii testis of Scheuchzer. A Lagomys and fossil Fox have also been found here. (See Geol. Trans. Lond. N. S. vol. iii. p. 287.

VOL. I.-33

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