234 DISPLACEMENTS OF STRATA 



(i) The Anticline is an upward fold or arch of strata, from 

 the summit of which the beds dip downward on both sides. The 

 curve of the arch may be broad and gentle, or sharp and angular, 

 or anything between the two. The line along which the fold is 

 prolonged is called the anticlinal axis and may be scores of miles 

 in length, or only a few feet. This may be illustrated by an 

 ordinary roof, which represents the two sides or limbs of the 



FIG. 90. — Anticline on the Potomac, Maryland. (U. S. G. S.) 



anticline, while the ridge-pole will represent the anticlinal axis. 

 Whether long or short, the fold eventually dies away, and thus the 

 summit of the arch is not perfectly level, but more or less steeply 

 inclined, and this inclination is called the pitch of the fold. In 



