372 On the Coal- Formation 



shells (jjlanorhis) along with the fruits of coniferse, willow- 

 leaves, &c. The two deposits, although belonging to very 

 different ages, have, therefore, been produced in similar cir- 

 cumstances, and very probably in shallow bays, or a kind of 

 estuaries, either at the mouth of some great river, or in places 

 overflown with enormous peat-bogs. 



We see, therefore, that the same causes can act in an ana- 

 logous manner at epochs very remote from each other, and 

 that true coal may be produced in a more recent forma- 

 tion. To this fact M. Pilla had formerly drawn attention, at 

 an extraordinary meeting of the Geological Society of France, 

 in 1839, at Boulogne-sur-Mer,* and of which we have ex- 

 amples in the Jurassic formation of Obernkircken, in Hesse, 

 which for ages has furnished coal to the whole of Northern 

 Germany, as well as in the Jurassic formations and green 

 sandstones of Entrevernes, Bottingen, Gersten in Austria, 

 Carpona in Istria, &c.t 



Besides, the aspect and properties of the coal-formation are 

 far from being an anomaly confined to the combustible of the 

 Maremma. These characters, forms, and the nature of the 

 rocks, which remind us of the more ancient formations, are the 

 ordinary phenomena everywhere observed in the structure of 

 Italy, and it is only to add a new fact to all these, which 

 prove to us the great diifer6nces in composition, arrange- 

 ment, and, in a word, general appearance, between the con- 

 temporaneous formations of the two sides of the Alps. It is 

 because the subterranean fires, which, in the north, have acted 

 only on the inferior part of the earth's crust, have here ex- 

 erted their power even to the highest stages. 



The coal of Monte Bamboli is, therefore, a new fact in 

 science, and one of great importance ; for it shews us that 

 this combustible may be pi'oduced in formations greatly supe- 

 rior to the true coal formations, which is in opposition to the 

 opinions generally held on this subject. But this fact is not 

 of less importance, since the minei'alogical and chemical pro- 

 perties are absolutely the same as those of coal ; the dispo- 

 sition and geological aspect of the formation is the same. 



If we consider that coal has no other probable origin than 



* Bulletin Je la Soc. Geol. de Prance, t. x., p. 419. 



t Boue, Guide du Geologue Voyageur, t. i., 3d partie, ch. i. § 11. 



