generally but few species, we may hope to be able to reconstruct these anomalous forms of the ancient world.

Distribution of fossil plants.-Notes from the Quarterly Journal of the Geological Society of London, Vol. I., 1845, p. 566, and Vol. II., 1846, p. 83.

The following extract, [with some modifications derived from Mr. Murchisson's paper on the Permian system,] from a memoir by M. Goeppert, of Breslau, well known for his investigations concerning the fossil remains of vegetables, possesses great interest, as offering a general view of the relative distribution of these remains.

Formations.

Lower Paleozoic System:

Grauwacké, silurian, or formations older than the carboniferous series, including the Devonian series, and the oldest coal or culm beds,

Permian system, or Upper Paleozoic: Carboniferous limestone,

True coal measures of Europe and North America, Lower new red sandstone, Permian series, containing, among others, a few species common to the carboniferous era,

Magnesian limestone and kupfer schiefer, chiefly marine fucoids, Permian system,

Gres bigarré, Bunter sandstein,

Triassic period; or Lower Secondary:

Muschelkalk,

Oolitic series,

Wealden formation,

Lower cretaceous beds,

Chalk,

Lower Tertiary.-Monte Bolca beds,

Other lower, tertiary,

Middle and upper tertiary.-Miocene and pliocene,

Unknown geological position,

4 11

169 1792

Summary of M. Gæppert's numerical distribution of Fossil plants. -The following table presented by Sir R. T. Murchisson at the meeting of the British Association, in 1845, embodies the same facts as are already announced in detail above.

It was further stated, that the number of fossil plants known to M. Adolphe Brongniart, in 1836, was 527. In the new list they amount to 1792! and it is seen that the carboniferous group contained more than half the known species of fossil plants; a remarkable circumstance, when it was considered that the great herbivorous land quadrupeds had no ascertained existence before the tertiary period.*

For a notice of the flora and fauna of the amber forests of the countries bordering on the Baltic, our readers are referred to the head of Prussian Pomerania, in this volume.

MICROSCOPIC OBSERVATIONS ON THE STRUCTURE OF COAL, LIGNITE AND PEAT.

Among other collateral subjects of interest, tending to throw light on the age, the history and the composition of coal, the mode of investigation through the agency of the microscope, is not altogether inappropriate.

Mr. Hutton, of Newcastle, has instituted a series of examinations of the substance of coals, through the aid of the microscope.

Professor Phillips addressed some observations to the British Association, in 1842, on this new test.

In consequence of the facilities afforded for polishing coal, and of examining it by means of transmitted light, some progress has been made in this mode of investigation.

By the process of combustion another method had suggested itself, for making apparent to the eye the vegetable tissues of which certain coal plants were composed. In the ashes of Staffordshire coal,—a variety not strictly bituminous or caking,-Mr. Phillips was impressed with the analogy they presented to the combustion of certain sorts of peat, of a laminated texture; and their microscopic examination showed abundant traces of a vegetable character.

* Report of the British Association, 1845.

In some anthracite ashes furnished by Sir Henry De la Beche, vegetable tissues were also found; and the same fact is also visible in the ashes of the Pennsylvania anthracites.

A paper was read to the Geological Society of London, January 9th, 1833, entitled "Observations on Coal," by W. Hutton. The author was led to this subject by pursuing the method of microscopic examination, so successfully employed by Mr. Witham; and from these observations much interesting information has been acquired, respecting the fine, distinct reticulation of the original vegetable texture, still discernible in the various species of coal, and showing the presence, in the Newcastle coals, of cells which are filled with bituminous matter, extremely volatile.

Another system of cells was discovered, different from the others, which he conceived was adapted for containing gas. These supposed gas cells are found empty, and of a circular form, and in groups which communicate with each other; each cavity having, in its centre, a small pellet of carbonaceous matter. The author establishes a clear distinction between these two classes of cells; for the anthracite of South Wales contains the gas cells, but is quite free from those which, in the other coals, are filled with bituminous matter. The anthracite of South Wales affords a free disengagement of inflammable gas when first exposed to the air.*

Additional light is thrown on this subject by a paper of M. Link, of Berlin, " on the origin of coal and lignites, according to microscopic observations."+

The professor remarks that there still prevail two different opinions relative to the origin of coal. The one sustains the view that it is a turf, peat or marsh of the primitive world; the other that it consists of the trunks of forest trees which have been brought together and here buried.

Ordinary peat consists of earthy matter penetrated by the roots or radical fibres of vegetables, with here and there some portions of leaves. This earthy part is composed of the cellular tissue of plants, whose structure has been so flattened by pressure, that it is often impossible to recognise them.

A second and better description of peat is sold at Berlin, under the name of tourbe de linum, which consists of cellular tissue, compressed in exceedingly thin laminæ.

A third variety, dug in Lower Pomerania, has acquired the appearance of fossil wood; being compact, and its fracture conchoidal and bright; yet still containing parts which resemble the debris of leaves. There remains no trace of ligneous structure. Some portions of this peat become partially transparent when plunged in olive oil; and still more so when they are coated with rectified oil from coal tar.

By observing a similar process with regard to coals, we are enabled to render a great portion of their parts transparent. It has, in this way, been found that the lignite or brown coal of New Granada, and

*Proceedings of Geol. Soc. of Lon. vol. i. 415.

† Annales des Mines, vol. xvii. p. 593. 1840.

the coals of Newcastle, of Bridgewater, Saint Etienne, and Lower Silesia, present a structure analogous to peat, and particularly to that of the compact tourbe de linum.

In these coals M. Link did not observe a ligneous structure, resembling that of solid wood.

The coals of Upper Silesia have enabled us to make, by means of calcination, a comparison with wood charcoal, particularly with that of birch, pine, and palm-the bactris spinosa. Calcination has restored to the cells or vessels all their distinctness, but did not effect any change in the pores or openings.

It would appear, then, that the fibrous coal which covers more or less the compact coal of Beuthen, in Upper Silesia, resembles burnt charcoal, seeing that its compact portion is peaty. All these coals belong to the most ancient formations.

The Muschelkalk coal in Upper Silesia, is turfy, but that of Diester, in the lias, appears to approach to wood.

The coal of the Quadersandstein of Quedlinbourg, exhibits evidently the wood of conifera.

The lignites of Greenland, in which retinasphalt occurs, are peaty in structure, as are those of Meissner, in Hesse.

In those of New Granada, the wood of the palm is discernible by means of the microscope.

In those of numerous positions in Germany can be traced the wood of conifera; while among those lignites which belong to the dicotyledones, but not to the conifera, may be ranked the Surterbrand, the Bersteinholz, the lignite of Meissner, and that of Brohlhale on the Rhine.

M. Göpper, professor at Breslau, has also pursued similar researches, with interesting results;* and has determined with great precision the character of many lignites in Prussia. Among the additional localities of lignites, which contain wood of the family conifera, and genus pinus, are those of Siegen in Westphalia; of Friesdorf near Bonn; of Salzhausen in Wetteravia; near Konigs-Bergen-Prusse, and in Hungary.

We cannot conclude this part of our subject without adverting to the investigations of Dr. Mantell therein. We regret that our limited space forbids us to extract more than the following passage from one of his latest publications.

66

Although the vegetable origin of all coal will not admit of question, yet evidence of the original structure is not always attainable. The most perfect bituminous coal has undergone a complete liquefaction, and if any portions of organization remain, they appear as if imbedded in a pure bituminous mass. The slaty coal generally preserves traces of cellular or vascular tissue; and the spiral vessels, and the dotted cells, indicating coniferous structure, may readily be detected by the aid of the microscope, in chips or slices. In many examples the cells are filled with an amber-coloured resinous sub

* Annales des Mines, vol. xviii. p. 448.

stance: in others the organization is so well preserved, that on the surface exposed by cracking from heat, vascular tissue, spiral vessels, and cells studded with glands may be detected. Even in the white ashes left after the combustion of coal, traces of the spiral vessels are discernible by a high magnifying power. Some beds of coal appear to be wholly composed of minute leaves, or disintegrated foliage; for if a mass be recently extracted from the mine, and split asunder, the exposed surfaces are found covered with delicate pellicles of carbonized leaves and fibres, matted together; and flake after flake may be peeled off through a thickness of many inches, and the same structure be apparent. Rarely are any large trunks or branches observable in the coal; but the appearance is that of an immense deposit of delicate foliage, shed and accumulated in a forest, (as may be observable in existing pine districts,) and consolidated by great pressure, while undergoing that peculiar fermentation by which vegetable matter is changed into a carbonaceous mass.

Professor J. W. Bailey has communicated an article in the American Journal of Science and the Arts, on some microscopic examinations which he has instituted, of the ashes of anthracite coal. He observed that on the surfaces of partly burned laminæ of coal, vegetable structure could be readily detected, and that often the tissues were presented in a state of unhoped-for preservation.

These specimens, the description of whose beauty and perfection can scarcely be exaggerated, present all the original markings of the vessels with a distinctness which leaves scarcely anything to be wished

for.

They may be examined either as opaque objects, in which the silex appears in relief against the black coal, and shows the form and markings of the tubes very finely; or still more satisfactory results may be obtained by melting some inspissated Canada balsam upon a plate of glass, and, while in a melted state, applying it to a surface of the coal upon which the ducts had been previously found to exist. When the balsam has hardened the coal may be taken off, and it will be found that it leaves, fixed upon the balsam, a thin layer of silica, containing perfectly preserved dotted vessels, which, when viewed as transparent objects, are nearly as distinct in their markings as if freshly obtained from a recent plant.

Among other inferences, derived from his early examinations, Professor Bailey draws the following:

1. That almost every layer of coal is composed of vegetable matter, which still retains very distinct traces of the original organic structure, and which, consequently, proves that it could never have been reduced to a homogeneous pulp.

2. That the plants which chiefly contributed to form the mass of the coal were not the ordinary dicotyledonous or monocotyledonous plants, but they more probably belonged to the acotyledons, among which the ferns and lycopodiacea present similar vascular bundles.

* Mantell's Medals of Creation, vol. i. p. 92.