152 
EFFECTS OF FRACTURE. 
or vapour, or of molten rock, subsequently 
to the consolidation of the coal beds. 
The broken appearance of rocks, to 
which is owing so much of their picturesque 
character in the landscape, is familiar to all 
lovers of scenery, and is principally owing to 
rents and fractures, not coincident with 
the orginal lamination of the mass, but of 
subsequent occurrence. In the most nu¬ 
merous class of instances, the broken strata 
do not lie in exactly the same plane, but 
the elevatory movement has thrown out of 
level one or other of the sides once evi¬ 
dently continuous. The line of fracture is 
sometimes a mere crack, at others a fissure 
filled with rubble from above, or with de¬ 
composed rock become clay, or a mass of 
crystalline porphyry or greenstone is insert¬ 
ed, and the communication intercepted be¬ 
tween the one side and the other. 
This state of things, which at first a})i)ears 
to be only calculated to produce disorder 
and confusion, and which in some cases cer¬ 
tainly has this effect, is yet on the whole 
admirably contrived to render the minerals 
accessible and workable. 
