240 



DISPLACEMENTS OF STRATA 



flexures are in contact and any further compression must be re- 

 lieved by a thinning of the beds. Cofttorted strata are thrown 

 into closed folds, which are connected by sharp, angular turns. 

 Plications are intense crumplings and corrugations of the strata. 



Fig. 98. — Closed recumbent folds, Doe River, Tennessee. (U. S. G. S.) 



Isoclinal folds are those which have been so bent back on them- 

 selves that the limbs of the flexures are all parallel, or nearly so. 

 When a series of isoclines has been planed down by erosion to a 

 level, the strata show a continuous, uniform dip and present a 

 deceptive appearance of being a simple, tilted succession of beds. 

 A still further compression of isoclinal folds produces fan folds. 

 In this structure the anticlinal is broader at the summit than at 



