8i6 . PRINCIPLES OF STRATIGRAPHY 



3. Fault scarp ridge — a topographic ridge bounded by two 

 roughly parallel fault scarps which face outward or toward the sur- 

 rounding low country. 



4. Fault scarp block — a topographic block bounded on all sides 

 by outward facing fault scarps. 



5. A tilted block — a topographic block bounded on all but one 

 side by fault scarps facing outward. The excepted side may be 

 faced by the fault scarp of another tilted block. 



6. A fault scarp basin — a topographic basin bounded on all 

 sides by fault scarps facing inward. 



7. A complex scarp basin — a topographic basin bounded on 



fault-line valley. 



most of its sides by fault scarps facing inward, but bounded by 

 warpings or in other ways on one or more sides. 



Secondary features due to erosion, 



1. Fault-line scarp. (Davis-4.) This is the fault scarp resur- 

 rected in the second cycle of erosion, after the obliteration of the 

 original fault scarps. This may face either way and may be 

 greater or less than the original fault scarp. If it faces in the same 

 direction as the original fault scarp it is rescquent; if in the opposite 

 direction it is obsequent. 



2. Faidt-line valley — a valley cut out along an old fault-line 

 after the obliteration of the original fault scarp. (Fig. 198.) 



3. TJie graben and fault scarp basin, the fault scarp ridges, 

 fault scarp block and tilted block may all be destroyed by erosion 

 and then resurrected in the second cycle of erosion. Such cases 

 may be designated by prefixing the word erosion — an erosion 

 graben, erosion fault scarp basin, erosion fault scarp ridge, etc. 

 See, further, Davis (4) and Hobbs (9a) ; also Chapter XXI. 



