globe at that early epoch. It is to be remarked, that if our theoretical ideas of the formation of the globe induce us to attribute this difference to the phenomena of temperature and pressure, which appear to have affected the rocks of the anthraxiferous epoch, this opinion is completely confirmed by the anthracitous state of the combustibles, subsequent to the coal period, which we encounter in the metamorphic formations. We cannot, in fact, doubt that, in the second case, the phenomena of heat and pressure are the modifying causes of beds which originally consisted of coal or lignite.

The tertiary LIGNITES have generally preserved their ligneous tissue so fully, that we can recognize, in many of the fragments, the nature of the constituent wood. The fir, the alder, the beech, and the oak, form the most frequent debris of the lignites of the Alps, and they thus denote a complete change in the vegetation of the earth since the coal period. They are the true fossil forests, which likewise differ from the coal beds by a more circumscribed accumulation, and by a less complete stratification.

In certain exceptional cases, the lignites have a compact structure, almost comparable to that of coal. They then constitute what is called common jet. This is the ordinary character of the lignites in the environs of Marseilles; which give rise to an annual production of more than a hundred thousand tons. These lignites form seven perfectly regular and stratified beds, within the tertiary basin, at Fuveau, Crest, Auriol, &c.; the thickness of each of which beds [from one to three feet,] preserves such constancy that it may be recognized by this character alone, in the divers parts of the basin. These beds are comprised between calcareous strata; they are subject to the numerous movements, inclinations, folds, faults, and upheavings which have disturbed the various portions of the tertiary basin.

Among these accidents, there is one which is peculiar to the lignites, and which is known under the denomination of mouillères. These consist of portions of beds where the lignite is so fissured and decomposed that it has become very permeable to water. The workings encounter the double difficulty of abundant infiltration, and a production of no value. In their normal state these lignites have much the appearance of coal, but they have not its quality. Nevertheless, in certain positions, in Tuscany, for instance, we find some small beds of a lignite sufficiently perfect to furnish a coke, on distillation.

The general character of lignite is such, that it cannot be considered as possessing a regularity comparable to the coal beds.

Portland Oolite Beds-Contain Zamia, fragments of which are found in the lower calcareous bed of the group-or perhaps in the inferior portion of the cretaceous series. These plants are accompanied by paladinæ or helices, which consequently indicate the passage of fresh water in the seas of this epoch, where are seen the remains of large coniferæ, rooted in the soil, analogous to the Araucaria, now strangers to the present climate of England. But in the midst of these coniferæ we find plants which have a resemblance to the Cycas and the Zamias of the tropical climates, and also the animal relics which approach to those of the same zone. The dirt bed of Portland, which incloses trees still in place, attests the existence of a vegetable soil, of earth almost dry, which rests upon the marine deposits. This bed has since been re-covered by very powerful beds of freshwater limestone, and then passes under the green sand which follows the chalk.

The Wealden group-incloses various vegetable debris-some of which resemble that of the Portland beds-and we meet with, in place, and in a

siliceous state, the trunks of Cycadeas; Mantellia Nidiformis. With these occur various species of coniferæ, besides the fragments of equisetacea and forms of a peculiar species.

Trias, or the Grès Bigarré, or copper group. This great formation, which in France has received the name of Trias, because it incloses three principal parts, is composed of deposits of sandstone and marls, of varied colours, which have given to the sandstone the name of Grès Bigarré, [red and white] and to the marls, that of Marnes Irisees. The two latter in England are known under the name of the upper new red sandstone and

red marl.

In this group vegetation has undergone great modifications. The ferns and the gigantic equisetacea have considerably diminished; while the coniferæ, on the contrary, have become more numerous plants, analogous to the Zamia, and perhaps to the Cycas, formed at that time an important portion of the flora of Europe; a prelude to the immense development which they made in the succeeding epoch-"lepoque jurassique," or lias.

Vegetable debris and combustibles of the Molasse.* This tertiary formation occurs above the Calcaire Grossier, in the environs of Paris.

The Molasse is very rich in combustible; it encloses the lignites of Languedoc; of Switzerland; the most part of those in Germany, as well as those of Cologne. All the lignites appear to have been principally formed by the conifera, of which we are able to recognize the tissue, either in the mass of combustible or in the wood which is disseminated in the midst of the various deposits.

It is known, however, that in this formation there are also many dicotyledonous plants, the wood of which is found disseminated here and there; sometimes in a silicified state, clearly exhibiting the tissue peculiar to this class of vegetables, and characterized, above all, by the presence of large longitudinal vessels.

Leaves also exist; often abundantly, even in the clays which accompany the lignites, and in these can be recognized distinctly the characters which the dicotyledones present. Among them are those of the walnut, the maple, elm, birch, &c.

There exist even fruits, which often cannot be distinguished from those which we find at the present day in our climate.

Finally, there are found in this formation the remains of monocotyledonous plants. This wood presents all the structure of the palms; that is to say, an assemblage of ligneous bundles, disposed longitudinally, without regularity, in the middle of a cellular tissue, as in Palmacites Lamanonis.

CUPRIFEROUS LIGNITES.

Vegetable remains under this form present themselves in various geological positions and circumstances, which will be noticed in the progress of this work.

In the provinces of New Brunswick and Nova Scotia they oocur in the regular coal measures. Mr. Henwood has mentioned this interesting factthat lignites, consisting of ferns and other coal plants occur impregnated with rich vitreous copper ore and coated with green carbonate of copper, on the Nipisiguit, near Bathurst in New Brunswick. These vegetable remains are, according to Mr. Logan, partly converted into coal, and partly replaced by gray sulphuret of copper. The same occurs in the neighbourhood of Pictou in Nova Scotia, in considerable quantities, and also within the limits * Cours Elémentaire d'Histoire Naturelle, par M. F. S. Beudant. † Mr. Henwood in Trans. Royal Geol. Soc. of Cornwall, 1840.

of the same coal-field at the Joggins, on the Bay of Fundy. On the Nipisiguit it has even been attempted to work the deposit as a copper mine; but, on account of the irregular distribution of the organic remains, the operations became uncertain and led to the abandonment of the work. This bed is from two to four feet in thickness.*

In Pennsylvania, United States, beds of vegetable stems, impregnated with vitreous copper and green carbonate, occur in the shale or argillaceous beds at the base of the Devonian or old Red Sandstone series. In two, or three instances, within our own observation, these were commenced to be worked as copper mines, but the quantity of ore was found insufficient for productive operations. The mineral occurs in the form of rich gray sulphuret of copper. So far as our remarks have extended, it is only the terrestrial and not the marine vegetation of this formation that is cupriferous.

In the State of New York, cupriferous lignites occur in about the same geological position, in the Catskill mountain series. They consist, like the preceding, of vegetable casts, replaced by gray sulphuret and carbonates of copper.t

Professor Del Rio mentions certain beds of this character with which he had become acquainted.

In Russia, in the carboniferous beds which are considered by Mr. Murchisson to be of the same age as the Zechstein of Germany and the magnesian limestone of England. The flora is peculiar to it; and the fossil stems and leaves of plants are very general indications of copper ore, which, in the form of gray oxide and green carbonate, is disseminated through or arranged around them.

The Kupper Schiefer of Germany represents this metalliferous deposit on a smaller scale.‡

In the Tyrol, in the upper tertiary coal beds of the valley of the Inncupreous vegetable fossils occur.

Thuringia is remarkable for a cupriferous schist, with lignites and fossil

fishes.

In the Spanish Pyrenees, Mr. Logan examined, within the coal measures, a bed which presented a combination of coal and gray sulphuret of copper, in the form of vegetable casts. These occupied an eighteen inch seam, cropping out regularly and extensively. It was then worked as a copper mine, and promised a profitable return.||

In Ireland, in a bog on the east side of Glendore Harbour, the peat was found to be highly impregnated with copper, which was extracted from the burnt ashes.

In Scotland and England, some of the beds of the old red sandstone have a green tinge, and the more argillaceous beds are mottled with red and green. The former hue arises from the oxide of iron, the different tints depending upon the amount of iron in the beds and on its state of oxidation, while the green colour is ascribed to the presence of copper. Whether vegetable casts occur in these beds as in the United States, we have not learned.

TURBARIES, PEAT-BOGS-TOURBIERES, PEAT-MOSSES.

In various portions of this work, under the topographical arrangement which we have adopted, will be found copious details in relation to this Report of the Geological Survey of Canada, 1 May, 1845, p. 63.

+ Mather's Fourth Report of New York Geology, p. 229.
Proceedings Geol. Soc. of London, vol. iii., p. 751.

Ibid, vol. i.

Logan's Report on the Geological Survey of Canada, 1 May, 1845, p. 64.

¶ Jameson's Mineralogy of the Scottish Isles,

useful combustible; the most recent deposit, if we may so employ the term, but nevertheless by no means the least valuable, of the class of fuels which we have to bring under consideration. It will be unnecessary, therefore, to recapitulate them in this place. Respecting the origin of these modern deposits, which bear some resemblance to coal-fields, it is not uninteresting to trace the process of their accumulation or development.

Turbaries, formed in depressions of the soil, where the shallow waters constantly remain, are found dispersed, here and there, on the surface of plateaux more or less elevated, or upon low plains, and often follow the direction of the valleys, whose hollows they fill. These deposits sometimes present several beds of the combustible, separated from each other by argillaceous, sandy, or calcareous matters; now and then filled with the remains of aquatic or terrestrial mollusques which still live in the country.*

They only originate under peculiar circumstances. They are formed neither in running waters, nor in deep lakes, nor in the transient pools of water which occasionally dry up. It is only produced in places where the waters stagnate, or are slowly renewed, and have an inconsiderable depth.

The production of peat is principally due to the accumulation of cellular vegetables, which are constantly submerged and which multiply with rapidity; such as the sphagnæ, confervæ, &c. To these are added a great number of terrestrial vegetables, which are brought thither by streams, either in their ordinary condition, or during inundations. Frequently, also, we find large trees, which are buried more or less deeply in the moss, and particularly in the lower parts, where they are accumulated upon the sands and clays which form the base. Sometimes these trees appear to be standing, but most frequently they seem to have been broken off on the spot, and thrown down near their roots, which are seen fixed at the bottom of the turbary. In certain cases they are extremely numerous, and seem to indicate entire forests which have been buried in the same spot where they grew, before the formation of the peat bog. All these plants conform to the existing vegetation. They consist of resinous trees, of oaks, birch, sometimes the ash, elms, &c. The first are generally the best preserved; they have, especially, maintained all their solidity, and are only blackened: the others, on the contrary, are to a certain extent, reduced to a rotten earth, which falls into powder on drying. We also frequently find the remains of mammifera in these peat-bogs, and these commonly belong to animals of the existing epoch. These are the bones of oxen, the horns of stags and roe-bucks, the tusks of wild boars, &c.

Turbaries or peat-bogs are abundant on the surface of the globe, in the cold and temperate regions, and are distributed in basins, like the coal-fields, more or less expanded, at all elevations, and occupy the various depressions of its surface. They are even on the summits of mountains, as in the Alps; on elevated plateaux, as in the centre of France; or in the lowest plains, where they cover sometimes immense spaces, as in Silesia, Prussia, Hanover, Westphalia, and Holland. Details will be found under each of these local heads in this volume.

If the majority of turbaries are formed on the main land, and entirely by fresh water vegetables, there are others which appear to have been deposited in the marshes which communicate with the sea; as the greater part of those in Holland. Some of these deposits consist of wrack or drifted seaweed and marine plants, such as we still see upon the flat and sandy shores of the ocean, and particularly upon those of Friezeland and Jutland.

It is remarked by M. Beudant, that the hypothesis which assimilates the coal beds to the turbaries is fortified by the different characters which they present. These are, on one side, the numerous debris of cellular cryptogami, which microscopic examination discovers in such combustibles as turf, the trees standing rooted in the middle of the deposits, and the remarkable preservation of the leaves in the schists; on the other, the disposition in basins, more or less extended, and isolated from each other, surrounded by the earlier rocks;-all circumstances which seem to indicate pools of water, and marshy places formed in the depressions of an open country. We frequently also observe that a certain number of small independent deposits form portions of a more extended basin; of a species of lake, filled with arenaceous contemporaneous matters, at the surface of which will be formed so many separate heaps of combustible: they are, as it were, inclosed in a species of ancient valleys, along whose length they are dispersed.

Certain desposits of lignite are evidently formed in the same manner as coal, of which they present the same characters, “allures;" but there are others which exhibit masses of wood, thrown pell-mell, more or less bituminized, preserving their tissue, buried by chance, in the middle of the sedimentary deposits; reminding us of those which are drifted by great rivers, which deposit them in the lakes, or which are transported to the middle of the seas.*

In France, where every description of fuel is valuable, the working of the turf pits is carefully attended to, and, in great measure, but not entirely, is under the surveillance of government officers. At the proper place we shall quote the annual returns of these officers to the minister of the interior; when it will be seen that the value of the turf is very far from inconsiderable, and approaches even to the value of the coal itself.

The usual process of cutting this turf is as follows. When the peat is above the level of the adjacent waters, as it is a substance always soft and easy to be cut, it is worked by digging small trenches with a succession of steps or grades of elevation, whose height is that of the spade which cuts them, say about one foot. These steps are separated by a breadth of at least three feet, upon which the workmen walk in file, one after the other, taking off, from each side, a series of prisms of about five inches in thickness. These prisms are immediately collected by the porters, chargeurs, who follow the cutters with wheelbarrows.

To raise thus a line of prisms from the whole length of a step or bench, is what is called raising a point of turf. The labourers can follow on the same step, gradin, in working out the successive points.

The extracted turf is carried to the drying floors, in the driest and best ventilated places in the vicinity. At first they deposit these prisms of turf flat on the ground, like bricks, and superposed to a trifling height; then, when they have acquired sufficient consistence, they are piled in walls open to the day, about three feet in height, which form a series of broken lines, in such a manner as to present solidity, and, at the same time, to permit the air to circulate without the wind being able to upset them. It is only after complete desiccation, that they are able to pile the peat in the form of stacks, which are then thatched with stubble, to prevent deterioration; for if it has not been well dried, it will heat, and if, on the contrary, it attain a point of desiccation too advanced, it will be crushed so as to occasion much waste. If the peat-bog be again covered by water, there will be a renewal of its original condition, but very often the workmen are compelled to work beBeudant, Cours élémentaire d'histoire naturelle, p. 115.

P