94 ELEMENTARY GEOLOGY 
which so closely resembles peat, that it still shows 
the plant remains and is so soft as to soil the hand. 
Bituminous coal has been partially transformed; and, 
although it is sometimes seen to contain plant frag- 
Fie. 40. 
Carbonaceous shale with thin laminz of coal and impressions of plants. Taken 
from mine above layer of bituminous coal. 
ments (Fig. 40), it does not look like peat or lignite, 
and is so hard that it easily passes for a rock. The 
next stage in the transformation is the~hard, black 
anthracite, and in some cases the change has gone so 
far that the coal is partly mineral carbon, or graphite. 
