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STATE OF FOSSIL PLANTS IN NEWCASTLE COAL-PITS. 343
We shall farther illustrate this point, by a brief description of the manner in which the remains of vegetables are disposed in the Carboniferous strata of two important Coal fields, namely, those of Newcastle in the north of England, and of Swina in Bohemia, on the N. W. of Prague.
The Newcastle Coal-field is at the present time supplying rich materials to the Fossil Flora of Great Britain, now
be discovered, thus affording the fullest evidence, if any such proof were wanting, of the Vegetable Origin of Coal.
"Each of these three kinds of coal, besides the fine distinct reticulation of the original vegetable texture, exhibits other cells, which are filled with a light wine-yellowcoloured matter, apparently of a bituminous nature, and which is so volatile as to be entirely expelled by heat, before any change is effected in the other constituents of the coal. The number and appearance of these cells vary with each variety of coal. In caking coal, the cells are comparatively few, and are highly elongated.—In the finest portions of this ccal, where the crystalline structure, as indicated by the rhomboidal form of its fragments, is most developed, the cells are completely obliterated.
"The slate-coal, contains two kinds of cells, both of which are filled with yellow bituminous matter. One kind is that already noticed in caking coal; while the other kind of cells constitutes groups of smaller cells, of an elongated circular figure.
"In those varieties which go under the name of Cannel, Parrot, and Splent Coal, the crystalline structure, so conspicuous in fine caking coal, is wholly wanting; the first kind of cells are rarely seen, and the whole surface displays an almost uniform series of the second class of cells, filled with bituminous matter, and separated from each other by thin fibrous divisions, Mr. Hutton considers it highly probable that these cells are derived from the reticular texture of the parent plant, rounded and confused by the enormous pressure, to which the vegetable matter has been subject."
The author next states that though the crystalline and uncrystalline, or, in other terms, perfectly and imperfectly developed varieties of coal generally occur in distinct strata, yet it is easy to find specimens whioh in the compass of a single square inch, contain both varieties. Erom this fact as also from the exact similarity of position which they occupy in the mine, the differences in different varieties of coal are ascribed to original difference in the plants from which they were derived. Proceedings of Geological Society. Land, and Edin. Phil. Mag. 3d Selies, Vol. 2 p. 302. April.
under publication by Professor Lindley and Mr. Hutton. The plants of the Bohemian Coal-field laid the foundation of Count Sternberg's Flare du monde primitif, the publication of which commenced at Leipsic and Prague in 1820.
Lindley and Hutton state (Fossil Flora, Vol. I. page 16) that " It is the beds of shale, or argillaceous schistus, which afford the most abundant supply of these curious relics of a former World; the fine particles of which they are composed having sealed up and retained in wonderful perfection, and beauty, the most delicate forms of the vegetable organic structure. Where shale forms the roof of the workable seams of coal, as it generally does, we have the most abundant display of fossils, and this, not perhaps arising so much from any peculiarity in these beds, as from their being more extensively known and examined than any others. The principal deposite is not in immediate contact with the coal, but about from twelve to twenty inches above it; and such is the immense profusion in this situation, that they are not unfrequently the cause of very serious accidents, by breaking the adhesion of the shale bed, and causing it to separate and fall, when by the operation of the miner the coal which supported it is removed. After an extensive fall of this kind has taken place, it is a curious sight to see the roof of the mine covered with these vegetable forms, some of them of great beauty and delicacy; and the observer cannot fail to be struck with the extraordinary confusion, and the numerous marks of strong mechanical action exhibited by their broken and disjointed remains."
A similar abundance of distinctly preserved vegetable remains, occurs throughout the other Coal fields of Great Britain. But the finest example I have ever witnessed, is that of the coal mines of Bohemia just mentioned. The most elaborate imitations of living foliage upon the painted ceilings of Italian palaces, bear no comparison with the beauteous profusion of extinct vegetable forms, with which the galleries of these instructive coal-mines are overhung. The roof is covered as with a canopy of gorgeous tapestry, enriched with festoons of most graceful foliage, flung in wild, irregular profusion over every portion of its surface. The effect is heightened by the contrast of the coal-black colour of these vegetables, with the light ground-work of the rock to which they are attached.- The spectator feels himself transported, as if by enchantment, into the forests of another world; he beholds Trees, of forms and characters now unknown upon the surface of the earth, presented to his senses almost in the beauty and vigour of their primeval life; their scaly stems, and bending branches, with their delicate apparatus of foliage, are all spread forth before him; little impaired by the lapse of countless Ages, and bearing faithful records of extinct systems of vegetation, which began and terminated in times of which these relics are the infallible Historians.
Such are the grand natural Herbaria wherein these most ancient remains of the vegetable kingdom are preserved, in a state of integrity, little short of their living perfection, under conditions of our Planet which exist no more.
VEGETABLES IN STRATA ON THE TRANSITION SERIES.* v
The remains of plants of the Transition period are most abundant in that newest portion of the deposites of this era, which constitutes the Coal Formation, and afford decisive evidence as to the condition of the vegetable kingdom at this early epoch in the history of Organic Life.
The Nature of our Evidence will be best illustrated, by selecting a few examples of the many genera of fossil plants that are preserved in the Strata of the Carboniferous Order, beginning with those which are common both to the ancient and existing states of Vegetable Life.
* See PI. 1. Figs. 1, to 13.
Among existing vegetables, the Equisetaceae are well known in this climate in the common Horse-tail of our swamps and ditches. The extent of this family reaches from Lapland to the Torrid Zone, its species are most abundant in the temperate zone, decrease in size and number as we approach the regions of cold, and arrive at their greatest magnitude in the warm and humid regions of the Tropics, where their numbers are few.
M. Ad. Brongniartf has divided fossil Equisetaceae into two Genera; the one exhibits the characters of living Equiseta, and is of rare occurrence in a fossil state; the other is very abundant, and presents forms that differ materially from them, and often attain a size unknown among living Equisetaceae; these have been arranged under the distinct genus Calamites,% they abound universally in the most ancient Coal formation, occur but sparingly in the lower strata of the Secondary series, and are entirely wanting in the Tertiary formations, and also on the actual surface of the earth.
The same increased development of size, which in recent Equisetacece accompanies their geographical approximation to the Equator, is found in the fossil species of this order to accompany the higher degrees of Antiquity of the strata in which they occur; and this without respect to the latitude, in which these formations may be placed. M. Ad. Brongniart (Prodrome, p. 167) enumerates twelve species of Catamites and two of Equiseta in his list of plants found in strata of the carboniferous order.
« See PI. 1. Fig. 2.
t Histoire des Vegitaux Fossils, 2d Livraison,
X Calamites are characterized by large and simple cylindrical stems, articulated at intervals, but either without aheaths,or presenting them under forms unknown among existing Equiseta; they have sometimes marks of verticillated Branches around their articulations, the leaves also are without joints. But the most obvious feature wherein they differ from Equiseta, is their bulk and height, sometimes exceeding six or seven inches in diameter, whilst the diameter of a living Equisetum rarely exceeds half an inch. A Calamite fourteen inches in diameter has lately been placed in the Museum at Leeds.
The family of Ferns, both in the living and fossil Flora, is the most numerous of vascular Cryptogamous plants.f Our knowledge of the geographical distribution of existing Ferns, as connected with Temperature, enables us in some degree to appreciate the information to be derived from the character of fossil Ferns, in regard to the early conditions and Climate of our globe.
The total known number of existing species of Ferns is about 1500. These admit of a threefold geographical distribution:
1. Those of the temperate and frigid zone of the northern hemisphere, containing 144 species.
2. Those of the southern temperate zone, including the Cape of Good Hope, parts of South America, and the extratropical part of New Holland, and New Zealand, 140 species.
* See PI. I. No. 6. 7. 8. 37. 38. 39.
t Ferns are distinguished from all other vegetables by the peculiar division and distribution of the veins of the leaves; and in arborescent species, by their cylindrical stems without branches, and by the regular disposition and shape of the scars left upon the stem, at the point from which the Petioles, or leafstalks, have fallen off. Upon the former of these characters M. Ad. Brongniart has chiefly founded his classification of fossil Ferns, it being impossible to apply to them the system adopted in the arrangement of living Genera, founded on the varied disposition of the fructification, which is rarely preserved in a fossil stale.