108 SOUTHERN CALIFORNIA GEOLOGY 



line such as San Gabriel and the San Bernardino High- 

 lands. These may represent uplifted blocks of pre- 

 existing surfaces which themselves are composed 

 of older and former structures. They are bordered 

 by more than one of the master fault lines of dif- 

 ferent directional trends, and in their relief may be a 

 record of more than one epoch of fault block displace- 

 ment. 



CONFORMATION OF THE PHYSIOGRAPHIC 

 LINEAMENTS TO STRUCTURE 



Most of the lineaments^ of the Southern California 

 physiography, including the direction of the folded 

 ranges and the borders of the fault-blocked plateaux 

 are coincident in occurrence with the direction of the 

 great structural trends, folds, rifts and fault lines — 

 which latter, in turn, may be classified by age and 

 direction into several categories, as will be shown. In 

 fact, the structure pattern of Southern California is 

 largely a duplicate of the relief patterns as shown 

 on Plate 1, so intimately are the two subjects related 

 to one another, although there are some few excep- 

 tions to the general rule. 



This relationship of structure to physiographic fea- 

 tures in Southern California is due to the fact that 

 the structural movements have taken place so lately 

 in geologic time (Pleistocene Epoch) that a sufficient 

 interval has not since lapsed for the destructive pro- 

 cesses of erosion, such as sculpturing of the arched 

 summits and rounding-off of the fault scarps, to efface 

 the relationship between the two kinds of phenomena 



'The ternx lineament is herein used to indicate conspicuous lines of the face 

 of the landscape, such as ridges, valleys, fault scarps, etc., just as it is used 

 in the dictionary sense for the conspicuous lines of the human countenance. 



