INITIAL AND YOUNG FORMS ON FAULTED STRUCTURES 



193 



In the initial stage of the new cycle thus introduced the physiographic 

 account of a fault should always begin with the description of the surface 

 previous to faulting; then proceed with a statement of the aspect, direc- 

 tion, length, and altitude of the fault scarp (or "vertical separation" of 

 the two parts of the prefaulting surface), with special mention of signifi- 

 cant local details — for example, the manner in which ridges and hills are 

 divided, valleys displaced, and streams ponded or accelerated, as well as 

 of local complications in the scarp caused by the doubling or splitting of 



Figure 2 



Figures 1 and 2. — The Sequence of Forms developed on faulted Structures 



the fissure — or, in brief, the account should slate the prefaulting surface 

 and the effects of faulting. 



This procedure is in accord with a general principle of prime impor- 

 tance in the explanatory description of land forms, namely, whenever a 

 movement of a land mass enters into its description — as in the case of a 

 regional uplift, a fault, or a coastal subsidence -the thing that suffered 

 the movement must he described as well as the nioxement of the thing: 

 otherwise the visible landscape as affected by the movement can not be 

 conceived; and the prefaulting forms should he described, h\ those who 

 adopl the method of "structure, process, and sta'je," in terms of these 

 three factors -thai is. its general structure should he stated, the proc- 



