370 ELEMENTARY GEOLOGY 
bedding, but in a direction making a high angle with 
this (Fig. 227). These layers in the metamorphic 
rocks are usually of minerals of different kinds. When 
examined in their place in the earth, it is found that 
the layers of banded minerals are parallel to one 
another over considerable distances, as if some power- 
ful force had been at work throughout the area. 
BiG. 225: 
Crumpling in a metamorphosed limestone. 
If the metamorphism has taken place in sedimentary 
rocks, the changes are often so pronounced that not 
only is the original nature of the rocks hidden, but even 
the stratification’ is destroyed, and nothing remains to 
tell whether the altered rocks were originally sedimen- 
tary or igneous. Possibly some small portion here or 
