Statistics of Coal

condition of the globe, independently of its natural dwelling-place, has, as it were, a central spot in which it flourishes best; and considering this spot as the centre of a circle, or rather as a zone, the plant degenerates in proportion as it approaches the limits of this district." The writer goes on to point out a very important circumstance, namely, that there is a difference of mean temperature, at present, of forty-one degrees of heat between the parallels in which coal has been discovered.* Between these, as regards the existing vegetation, the diversity in the genera and species of plants, at present, is very great; so much so, indeed, that there is no resemblance between the floras of the two extreme points. At the time, however, of the true coal formation, it is now admitted that the flora of these two remote parallels was nearly the same, both as to genera and species, and in this respect strongly contrasted with the present condition of things.

Fossil Plants of the class Phanerogameæ.-The monocotyledonous family of this class, in the fossil state, commence in the London clay tertiary formation, and, until lately, were thought not to descend lower in the geological series than the oolites, or the Waelden beds, the Portland oolite and the Lias.

The cycades [Cycas Zamia] form the connecting link between the ferns and the palms, while, according to the authorities last cited, the sigillaires differ not more from the aborescent ferns [Caulopteris,] yet existing, than the stems of the calamites, the bactris, and other arundinaceous palms,† which order contains, in the recent state, eighteen genera and twenty-nine species. Zamia were very abundant in the oolite period. Eleven species occur in the coal of the Yorkshire oolite alone.

Distribution of the Vestiges of Palms in the Geological Formations.-Prof. Unger states, first, That no vestiges of palms have been detected in the earliest rocks which contain the organic remains of maritime and terrestrial plants.

Second, That palms bore some small part in the vegetation at the period of the coal formation. He names four species or forms, two of which occur in the coal schist of Swina, Bohemia, one in sandstone of the Ural Mountains, and one from Rajemahl, North India; also two undescribed species from the coal formation of Silesia.

Third, The flora of the red sandstone, above the coal series, although it has been very imperfectly preserved, and its scanty remains but little studied, Unger thinks was not materially different from that of the coal formation. But the fossils of this era, which have been referred to palms, he thinks are very doubtful. In the Quadersandstein, Goeppert found some vestiges in Silesia. From the next series, the oolites, the four species of Carpolythes, described by Lindley and Hutton, may be mentioned.

Fourth, and finally. In the tertiary, palms reappear, and the

This approaches closely to the range we have assigned to the coal formations.

† Histoire des Vegetaux Fossiles.

American Journal of Science, July, 1846.

number of species far surpass that of all the other formations together.

Subdivision of tertiary positions,

In the chalk and eocene,

miocene

pliocene,

4 species, also fruits.

26 species on the European continent. 4 species, island of Antigua.

Fossil Cryptogamece.-Many years ago Count Sternberg noticed that out of one hundred and fifty species of plants belonging to the old coal formation, one hundred and thirty-eight were vascular cryptogamea soon afterwards M. A. Brongniart stated that the vascular cryptogamous plants had a vast numerical proportion in our great coalfields; and, in fact, even at that early period, he had ascertained that out of two hundred and sixty species, discovered in that formation, two hundred and twenty belonged to this class.

This arrangement has of late received very considerable modifications; chiefly through the aid of a microscopic elucidation of their structure as we shall proceed to show. Messrs. Lindley and Hutton, A. Brongniart and others, now withdraw the sigillaria, the stigmariæ and the calamites, from this numerous group; separating them from the associated filices or herbaceous ferns, and the caulopteræ, which only comprise the true arborescent ferns.

The fossil cryptogamous series embraces the following:

Sphenopteris,

Species.
36

6146 species belonging to the filices or herba28 ceous ferns, chiefly of the coal beds.

Cyclopteris,

Nevropteris,

Pecopteris, 76

Equisetaceæ,

The true aborescent ferns.
Some species.

Lycopodiaceæ, 848, belonging to lycopodites and club mosses, Lepidodendrons, 40 of the coal formation.

III. ACOTYLEDONEÆ, OR IMPERFECT.

Vegetable beings composed of a cellular tissue unprovided with vessels, and of which the embryo is without cotyledons. The divisions of this family are as follows:

Fucoides, of many species, are exceedingly abundant in the silurian or transition formations, from the coal series down to the primitive rocks. In certain portions of the silurian series of North American rocks, this class of plants is surprisingly prevalent, and characteristic. The oldest of these formations present us with nothing but cellular-leaved marine plants. Many species of fucoides in the copper slate of Mansfeld.

The prevailing vegetable forms of the chalk formation are those of marine and freshwater plants-fuci and najades.

Of confervæ are three fossil species; of Algæ, nine species; and of Naiades, four species, in the cretaceous group.

Distribution of Fossil Vegetation.-M. Alex. Von Humboldt has stated in a recent work, that it is in the Devonian strata that a few cryptogamic forms of vascular vegetables, equisetacea and lycopodiaceæ, are first encountered. After these strata, we arrive at the coal formation, the botanical anatomy of which has made such brilliant progress in recent times. These comprise nearly four hundred species, including in their number not only fern-like cryptogamic plants, and phanerogamous monocotyledons, grasses, yucca-like lilaceous vegetables, and palms, but also gymnospermic dicotyledons, coniferæ and cycadeæ. Fossil coniferæ have been found in the old coal formation of England and Upper Silesia; while cycadeæ are contained in that of Radnitz, in Bohemia, and Königshütte, in Upper Silesia. The cycadeæ attain their maximum in the Keupfer strata and the lias, where about twenty different forms make their appear

ance.

The lignitic or brown coal strata, which are at present in every one of the divisions of the tertiary period, amongst the earliest forms of cryptogamic land plants, exhibit a few palms, many conifere with distinct annual rings, and frondiferous trees, of more or less decided tropical character. In the middle tertiary period we observe the complete recurrence of the palms and cycadeans; and in the last members of this epoch, at length, strong resemblances to our present flora. We come suddenly upon our pines and firs; our cupuliferous tribes; our planes, and our poplars. The dicotyledonous stems of the lignites are frequently distinguished by gigantic thickness and vast

age.

A trunk was found near Bonn, in which Noggerath counted 792 annual rings.

With relation to coal vegetation, M. Humboldt remarked that where several series of coal strata lie over one another, the genera and species are not always mixed; they are rather, and for the major part, generically arranged, so that only lycopodites and certain ferns occur in one series of beds, and stigmariæ and sigillariæ in another.*

In elucidation of the progress made in fossil botanical discovery, Mr. Adolphe Brongniartt has lately observed that the further we proceed in the series of ages towards the earliest geological periods,

# Cosmos.

† Comptes Rendu, Dec. 29th, 1845-and Annual and Mag. Nat. Hist., February, 1846.

the further are we removed from the actual creation, and the greater do the differences between the living and fossil beings become. Thus, most of the fossil plants of the tertiary strata belong to genera in actual existence, and merely present specific differences.

Those of the secondary strata may, undoubtedly, almost always be referred to known families, but appear in most cases, to require the formation of new genera.

Lastly, in the older strata, particularly in the coal formations, many of the fossil plants cannot be classed in families at present existing, and ought to constitute new groups of equal importance.

He adds that new and hitherto very rare specimens, which have been collected and carefully studied in England, Germany, and France, have caused important changes relative to the plants which he had previously considered as vascular cryptogamia. This advance is owing to the discovery of portions of stems of these plants having the internal structure in a state of preservation. They have shown that the sigillariæ, stigmariæ, and probably most of the calamites, are not plants nearly related to the ferns, lycopodia, and equiseta, but to distinct families of the dicotyledonous gymnospermous group, more nearly approaching the coniferæ and cycadex.

Hence, at the period of the coal formation, vegetation would have consisted entirely, or nearly so, of two of the great divisions of the vegetable kingdom: the ACROGENOUS CRYPTOGAMIA, represented by the herbaceous and arborescent ferns, [the latter reduced to the true caulopteris,] the lepidodendreæ, a family nearly related to the lycopodiacea, and some equisetacea; and the GYMNOSPERMOUS DICOTYLEDONS, comprising the sigillariæ, [sigillaria, stigmaria, lepidofloyos,] the calamitaceæ, the coniferæ, and probably the asterophyllea, [asterophyllites, annularia, and sphenophyllum.]

Mr. Brongniart proceeds to describe a plant which closely approaches a family of the gymnospermous dicotyledons still in existence, the cycadex, and of the genus noggerathia. This plant, at first known to M. de Sternberg, by the impression of a single leaf, from the coal formation of Bohemia, has since been observed in the coal shales of Newcastle, in those of Silesia, in the Permian sandstones of Russia, and many new species of the same genus are in the schists and coal sandstones of France.

He considers, with M. Humboldt, that each stratum of coal is the product of a peculiar vegetation, frequently different from that which precedes and that which follows it,-vegetations which have given rise to the superior and inferior layers of coal; each stratum resulting, in this manner, from a distinct vegetation, is frequently characterized by the predominance of certain impressions of plants, and the miners, in numerous cases, distinguish the different strata, which they remove, by the practical knowledge they possess of the accompanying fossils. Any seam of coal and its overlying rock or slate, should consequently contain the various parts of the living plants at the period of its formation; and by carefully studying the association of these various fossils, which form so many special floras, containing

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, contain-
ing, 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,