245 
can it be supposed, that coal can have been formed from vegetables, 
when considerable beds exist at the height of twelve thousand feet 
in the Cordilieres of Peru, and at more than six thousand feet in 
height on the Dauphinese Alps ; where, he adds, these beds have 
been deposited, at a time when vegetables did not yet exist, and 
when the waters covered the whole surface of the globe. How 
otherwise, he asks, can we account for the regular alternate beds of 
coal and layers of stone ; such as, for example, are seen in the col- 
liery at Liege, where there are sixty-one beds of coal, alternating 
with as many layers of stone, of a vast thickness*. 
The latest writer of celebrity on this subject, is Mons. Fourcroy, 
who, speaking of the origin of this substance, says, the greatest part 
of naturalists consider coal as the product of the remains of wood, 
which has been sunk, and afterwards changed by the water, and by 
the salts of the sea. Coal, he observes, seems to owe its formation 
to the decomposition of an immense quantity of marine and terres- 
trial vegetables, and to the separation of their oil, which becomes 
united to the aluminous and calcareous earth. It cannot be denied, 
he remarks, that animal matters also enter into its composition ; and 
afterwards observes, that a considerable quantity of ammonia is 
yielded by the distillation of coal, which favours the opinion of its 
animal origin, since bodies belonging to this class of compound 
substances always yield ammonia during their distillationf . 
Evident indecision is observable in the foregoing opinion, re- 
specting the formation of coal ; doubtlessly arising from Mons. 
Fourcroy’s disposition to countenance the idea of animal bodies 
having contributed greatly, and perhaps even more than vegetables, 
to the formation of some kinds of bitumen. Want of that precision,. 
* See article Houille, Dictionnaire d’Histoire Naturelle. 
f Systeme des Connoissances Chymiques, tom. viii. p, 241 et 244.. 
