612 



COAL. 



THIS vain ible substance, here included among 

 the rocks, for the reasons formerly assigned, is 

 found in various parts of the world, but most con- 

 spicuously in Britain. It occurs both in the 

 primary and secondary strata ; but so rarely and 

 in such small quantity in the former, as scarcely 

 to deserve notice here, were it not for the sake of 

 the connection in mineral characters between the 

 two. 



In the primary rocks, it has been found in 

 gneiss, in micaceous schist, and in argillaceous 

 schist; forming small laminae, or scattered por- 

 tions ; and thus it occurs in several parts of the 

 continent of Europe. It has also been found in 

 detached lumps in limestone, in Norway, and in 

 an antient conglomerate rock, in France. 



In the secondary class, it forms beds of con- 

 siderable extent, alternating with rocky or earthy 



