COAL EPOCH. 193 



From this moment lands were covered with vegetation, in arbo- 

 rescent ferns, equisita'ceae, &c., sufficiently abundant to form the 

 masses of anthracite found in the Devonian formation. The seas 

 were then inhabited by trilobites, orthoce'ratites, orthis, productus, 

 different kinds of terebra'tula and several species of polypa'ria, 

 of the same genus as those found in madreporic reefs, which, as 

 * r eli as the tree-ferns, indicate a climate analogous to that of the 

 present tropics. All these circumstances show that heat was not, 

 in that epoch, distributed over the surface of the globe as it now is. 

 Without doubt, the increase of temperature, from the surface to the 

 interior, was more rapid ; all springs were warm ; and, according 

 to M. Elie de Beaumont, the fogs, which were the result, hinder- 

 ing radiation, in the absence of the sun, everywhere tempered the 

 rigour of winter, and thereby augmented tho mean temperature 

 of the seasons. 



Coal epoch. The upheaval of the Ballons, in bringing " to day" 

 the Silurian and Devonian deposits, no doubt, increased the extent 

 of lands, and more or less changed their configuration. Vegeta- 

 tion must have been prodigiously developed, at that time, and over 

 vast surfaces ; which is proved by the enormous mass of coal 

 formed, and the manner in which the deposits are piled up. On 

 one hand, the carboni'ferous limestone, and the different marine 

 beds found in the midst of the sandstone of the coal formation itself, 

 seem to indicate at first a deep sea, and perhaps afterwards an 

 immense maritime marsh, which extended from Ardennes and the 

 Hartz to the ancient mountains of the British islands. On the 

 other hand, the numerous coal basins known to exist in the surface 

 of France and central Germany, clearly show there were extensive 

 lands on which marshes were found, here and there, in which were 

 formed, just as peat-bogs are in our times, all the coal deposits 

 we have discovered. 



The ancient and uncovered formations, which constitute Brittany 

 and the central plateau of France, clearly indicate high land, on 

 which are found the lakes of Bayeux, duimper, Laval, and Vouvant, 

 placed perhaps in the anfractuosities caused by upheaval of the 

 ballons ; then those of Burgundy, Limousin, Auvergne, Forez, &c., 

 situated on a direction parallel to the elevation of the Hundsruck. 

 This land, the limits of which cannot be fixed, extended at least to 

 a peninsula towards Strasburg. 



To the east of this land, and perhaps united to it, there is another, 

 which was evidently uncovered, because there is nothing of the 

 penine formation deposited on it. The latter probably extended 

 over the space now occupied by Inspruck, Milan, Briancon, 

 Genes, Nice, Toulon, and to the island of Corsica. Towards Toulon 

 are the marshes in which was formed the coal now found in that 

 part of France. 



Lands also evidently existed over the space occupied by Bohe- 



