184 SOUTHERN CALIFORNIA GEOLOGY 



rocks between floating and drifting blocks of denser 

 rocks may have also been quite possible, as in the in- 

 stance of the Badlands Range. Some of the causes 

 which have produced the folding and faulting are dis- 

 cussed in a later chapter. 



THE SIMPLE TYPE OF FOLDED RANGES 



There are several ranges in Southern California in 

 which the simple, elongated, anticlinal type of structure 

 prevails. These are reflected in varying degrees in the 

 physiography. The conformation of physiography to 

 structure varies in accordance with the newness or old- 

 ness of the ranges. Conspicuous examples of a close 

 relationship of this type are the Dominguez Range and 

 certain of the Ventura Ranges. The Solomon Hills of 

 the Santa Maria District are another example. 



The trends of the simple-fold ranges are usually 

 associated with parallel lines of master faulting and 

 are mostly the products of the same great stresses. 



The simple-folded range structure in Southern Cali- 

 fornia sometimes alternates with the synclinal val- 

 leys. The lines of folding also usually have sags or 

 saddles in them at more or less regular intervals which 

 divide them into bead-like domes, such as those in 

 which the pools of oil are found, along the courses of 

 the Dominguez and Ventura Ranges. 



RELATION TO SURFACE 



The physiography of the folded ranges varies in per- 

 fection of contour and conformation with the nature 

 of the structure (flatness or compactness of the 

 arches) and in proportion to the ages of the folds. The 

 more perfect and symmetrical folds are found in the 

 newest ranges, like those of the Dominguez and 



