494 



M. Virlet in the Dictionnaire d'Hist. Naturelle, where in his late 

 article " De I'Origine des Combustibles Mineraux," he speaks of 

 certain carboniferous deposits of Ireland, (those alluded to by Mr. 

 Weaver before mentioned,) as well as others examined by M. Voltz 

 in the Black Forest, also the culm beds of Brittany, and those of 

 the department of La Sarthe, as all belonging in age to the newest 

 transition formations, " terrains de transition les plus recens." 



Mr. De la Beche alludes to another discovery of coal plants 

 implying as great an anomaly as that which he had imagined to 

 occur in Devonshire, and by which he was himself once led into 

 error during an Alpine excursion, about eighteen years since, when 

 he met with coal plants in the schists of the Col de Balme, in 

 Switzerland. He then inferred that the beds belonged to the true 

 coal measures, but M. Elie de Beaumont afterwards proved them 

 to be lias ; that is say, he identified them with other rocks not far 

 distant in the Alps, which were shown to be lias by containing Belem- 

 nites and other fossils. Mr. De la Beche was at first sceptical on the 

 point, but after revisiting the Alps, he came round to the same opi- 

 nion. Having therefore been in one instance misled by relying on 

 the fossil vegetables of the coal as affording a good chronological 

 test, he naturally attached but small value to the same testimony as 

 a criterion of the age of another set of rocks in Devonshire. Now 

 you will easily understand that a geologist, who is once persuaded 

 that the same plants flourished in European latitudes from the pe- 

 riod of the true coal to that of the lias, will be ready to concede 

 without difficulty the probable existence of the same plants at an 

 era long antecedent to the coal. We know that between the depo- 

 sition of the coal and the lias there were successive revolutions in 

 the races of animals which inhabited the waters, the zoophytes, 

 moUusca, fish, and, as far as we know them, the reptiles having been 

 changed again and again ; so that the fossils of the mountain lime- 

 stone differ from those of the magnesian limestone or zechstein, 

 these again from the organic remains of the muschelkalk, and these 

 last from those of the lias. If we are to believe that the same 

 plants survived on the land, while such fluctuations in animal life 

 occurred in the waters, why should we not imagine the longevity of 

 the same species to have been still greater, so that they began to 

 exist even before the deposition of the old red sandstone ? But let 



