THE CRUST OF THE EARTH. 



nearly five hundred feet below the surface, on which numerous 

 trees have been found standing erect from two to eight feet 

 in circumference, with their roots struck into thin layers of 

 coal. 



173. " In a colliery near "Wolverhampton," says Hugh Miller, 

 " the bottom coal rises to view, and where the surface has been 

 cleared of the alluvial covering, it presents the appearance of a 

 moor on which a full-grown fir- wood had been cut down a few 

 months before, and only left the stumps behind. Stump rises 

 beside stump, to the number of seventy-three in all : the thickly 

 clinging roots strike out on every side into what seems once to 

 have been vegetable mould, but now exists as an indurated 

 brownish-coloured shale. Many trunks, sorely flattened, lie 

 recumbent on the coal; several are full thirty feet in length^ 

 while some of the larger stumps measure rather more than two 

 feet in diameter. There lie> thick around, Stigmariae, Lepidof- 

 dendra, Calamites, and fragments of Ulodendra; and yet with 

 all the assistance which these lent, the seam of coal formed by 

 this ancient forest does not exceed five inches in thickness. Not 

 a few of the stumps in this area are evidently water-worn. The 

 prostrate forest had been submerged, and molluscs lived, and 

 fishes swam over it. This upper forest is underlaid by a second, 

 and even a third : we find three full-grown forests closely packed 

 oip in a depth of not more than twelve feet." * 



174. M. Alexandre Brongniartf describes a coal-pit at Tfeuille 

 mear St. Etienne, in the neighbourhood of Lyons, which contains 

 enormous stems of Calamites and other trees in erect positions 

 (fig. 87). These and similar effects are considered as proofs that 

 the coal was produced by the submergence of a forest which grew 

 upon the spot. This particular mine is very favourable for observa- 

 tions being in the open air, and presenting a natural succession of 

 the strata of clay, slate, and coal, with four layers of compact 

 iron-ore in flattened nodules, accompanied and even penetrated 

 by vegetable remains. 



The upper ten feet of the quarry consist of micaceous sand- 

 stone, which is in some instances stratified, and in others has a 

 slaty structure. In this bed are enormous vertical stems 

 traversing all the strata, and appearing like a forest of plants 

 resembling the bamboo or large Equiseta petrified on the spot on 

 which they grew. The stems are of two kinds, one long and thin, 

 from one to four inches in diameter, and nine or ten feet high, 



* First Impressions of England and its People, by Hugh Miller, p. 223. 

 1* Notice sur les Vegetaux fossils traversants les Couches du Terrain 

 houilleux, par M. A. Brongniart, Paris, 1821. 

 126 



