SOUTH WELSH DEPOSIT. 463 If from this we deduct one half for waste, and for the minor extent of the upper beds, we shall have a clear supply of coal equal to 32,000,000 tons per square mile. Now if we admit that 5,000,000 tons of coal, from the Northumberland and Durham mines, is equal to nearly one third of the total consumption of coal in England, each square mile of the Welsh coal-field would yield coal for two years' consumption; and as there are from 1,000 to 1,200 square miles in this coal field, it would supply England with fuel for 2,000 years after all our English coal mines are worked out. It is true, that a considerable part of the coal in South Wales is of an inferior quality, and is not at present burned for domestic use; but in proportion as coals become scarce, improved methods of burning it will assuredly be discovered, to prevent any sulphureous fumes from entering apartments, and also to economise the consumption of fuel in all our manufacturing processes."* * Bakewell's Introduction to Geology, 1828, p. 178, et seq. CHAPTER XXV. FOREIGN COAL DEPOSITS. Importance of Foreign Coal Deposits to Great Britain -General Phenomena of the Carboniferous Strata similar in different Countries-Organic Remains and accompanying Rocks-Independent Coal Formation of Werner-Occurrence of Coal in Spain -Near Dresden-In Silesia-Vast Deposits in France-In Belgium-Fire Damp-Coal Fields of Germany-Fossil Fishes-Coal in Sweden, Norway, and Poland-Immense Depositories of Anthracite and Bituminous Coal in North America— Scarcity of Fuel in some parts of South AmericaRhode Island, Canada, and Australia contain Coal -Strata on Fire at Cape Breton-European Localities of Lignite and Fossil Wood. ALTHOUGH the design of the present work, as to its more immediate bearing, might be considered as completed by the foregoing Chapters, a few brief notices of one branch of the subject in reference to other countries may be appropriately introduced in conclusion. The subject of foreign coal deposits is by no means one exclusively interesting to the geologist; it involves important considerations of a IMPORTANCE OF THESE TO BRITAIN. 465 commercial nature in relation to Great Britain. For, not only must the coal trade of this country be in some degree influenced by competition with the supply of so important an article from other and remote sources; but the districts containing coal mines, may be expected, hereafter, to become, in certain cases, the seats of manufactures, perhaps rivalling in importance, or it may be, surpassing those which, owing to the abundance and accessibleness of our fossil fuel, this country has long carried on so advantageously. It has been remarked, that the great coal formation appears to abound most under the polar circle, and in the two temperate zones, but it is rarer towards the equator: a geographical distribution supposed to be connected with its formation. Although, as might be expected, the carboniferous strata, when viewed on the large scale, occasionally present some anomalies, as compared with the corresponding series in our own country,—yet still, the similarity in certain striking particulars is much more common and remarkable. This is more particularly manifest in the occurrence of sandstone and bituminous shales, or beds of compressed and indurated mud; together with those vegetable impressions which, although exhibiting specific differences from those met with in Britain, belong, for the most part, to analagous types. We have already adverted to the opinion of M. Brongniart, that at the epoch of the coal formation, there existed eqiseta, or horse-tail plants, upwards of ten feet high, and six inches in diameter; tree-ferns, of from forty to fifty feet in height; and arborescent lycopodiacea, of from sixty to seventy feet high. Of the above classes of vegetables, as Mr. Lyell observes, the species are all small at present, in cold climates ; while, in tropical regions, there occur, together with small species, many of a much greater size; but their development at present, even in the hottest parts of the globe, is inferior to that indicated by the petrified stems of the coal formation. If the gigantic size and form of these fossil plants are remarkable, still more so is the extent of their geographical distribution : for impressions of arborescent ferns, such as characterize our English carboniferous strata, have been brought from Melville Island, in lat. 75°*. The geological equivalent of our great carboniferous group of rocks, as met with on the continent of Europe, is what is called by the disciples of Werner, the Independent Coal Formation. It does not occur in the Alps, or in the basin of the Po; indeed, it is asserted, that the true coal measures do not exist in Italy; and this remark has, by some persons, been hastily extended to Spain and Sicily. Opinions, on this point, exhibit, as might be expected, various discrepancies, as geological enquiries have hitherto been limited, if not in their range, certainly in the number of scientific stations, and accredited observers at remote places; while travellers and geographers have commonly used the term "coal," in the most loose and popular sense. As already intimated, the coal strata in Europe do not always conform to British analogies; and in some localities there seems so little agreement, that individuals pretending to geological acuteness have been misled thereby. In Spain, coal deposits are known in Andalusia, Estremadura, Catalonia, Arragon, and Castile, and the Asturias: but the beds are commonly thin, and the workings, for the most part, of little im * Principles of Geology, vol. i. p. 101. SPAIN, FRANCE, &c. 467 portance it seems, however, that one exception must be made with reference to the last-named locality, where the beds which are described as "vast," and supposed by Professor Hausman to be subordinate to the immense iron-stone hills near Bilboa.* In Portugal, there are some trifling coal works. True coal measures exist at Postchapel, near Dresden, at Friedland, and near to Ternovitz, in Silesia; in the latter place, there are vast deposits of valuable fuel; as also at Namur, Saare Brooke, and St. Etienne in France. One of the richest deposits of coal that is known, forms the nearly continuous series of coal basins placed in a belt about one hundred and fifty miles long, and six miles broad, which crosses the north of France, containing the coal mines of Valenciennes, Conde, Mons, Namur, Liège, and at the last-named place, the measures are said to comprise eighty-three beds. They produce annually more than seventy millions of quintals of coals, worth thirty millions of francs; and they employ about thirty-five thousand colliers. In 1826, it was stated in the Annales des Mines, that about forty departments were known to contain coal, and a list of the localities is given in that work.‡ Several of the deposits, however, it was admitted, could scarcely be said to be more than known; others * In Spain, charcoal is commonly used for fuel both in the kitchen stoves upon which culinary operations are performed, and in the brasero's, or warming pans, placed to air the sitting rooms. The mountains of New Castile, which are covered with noble trees, supply the inhabitants of the plains, and also the capital with charcoal for fuel; and it is common in the streets of Madrid to meet with asses bearing large panniers of this commodity, accompanied by a boy shouting "carbon! carbon!" + These localities of foreign coal are mostly derived from Phillips and Conybeare, Dr. Ure, and Mr. De la Beche. Edin. Phil. Journ. vol. xiv. pp. 252-257, where the account is translated from the Periodical above cited. |