12 [April, 1S41- 



Another resemblance between the two kinds is that in the an- 

 thracite beds, spaces partially vacant are found to contain masses, 

 with a puffy aspect on the exterior, so strongly resembling coke, 

 that it might be difficult at the first glance to distinguish a fragment 

 of it from a piece of artificial coke. Natural coke is also found in 

 connection with beds of bituminous coal, especially where the latter 

 are in close proximity with primitive strata as in the mines of 

 Virginia. 



When coal contains a large proportion of earthy matter, and is 

 deposited in thin lamince, it will, in the state of anthracite, be found 

 to part with great difficulty in the direction of the surfaces of depo- 

 sition. It will then be seen to give fractures, developing a multi- 

 tude of small conchoidal surfaces, This is by the miners termed 

 bony coal ; and that it well deserves its name may be evinced by 

 its actually being so hard as sometimes to strike fire with steel. 



Coal occasionally assumes the appearance of well defined rhombic 

 prisms and octaedra, occasionally with striated surfaces, in which 

 cases, though the cleavages be difficult and obscure, they are never- 

 theless practicable. 



