DAVIS: MOUNTAIN RANGES OF THE GREAT BASIN. 159 
In the early and later stages of faulting, both faces of a lifted moun- 
tain block would present features similar to those already described as 
occurring on the faulted face of a tilted block, while the upper surface 
of the lifted block would exhibit features dependent on revived erosion, 
such as are commonly found in uplifted regions. In young blocks of 
this kind, the intensity of revived erosion would rapidly increase toward 
the block border; in this respect the upland of a young block would 
present features very similar to those found in the Arizona plateaus that 
border on the Colorado canyon, or in the plateaus of western Germany 
which border either on the Rhine gorge below Bingen or the Rhine 
Figure 13. 
Diagram of talus at the base of a vertical block front. 
graben above Bingen ; for so far as the dissection of an upland is con- 
cerned, it matters little whether its streams descend by a fault scarp to 
a lowland or by a canyon wall to a river. 
In older uplifted blocks of longer continued faulting, the contrast of 
scarp and upland would be weakened ; and after the faulting was far 
advanced, the contrast would disappear entirely. The battered retreat 
of both scarps, gnawed by retrogressive ravines, would result in trans- 
forming the upland into a more or less serrated ridge. 
Many special conditions might be imposed upon these general deduc- 
tions by assuming particular features of prefaulting relief and drainage. 
These conditions need not be entered upon here, because my observa- 
tions did not go far enough to provide a large variety of facts with which 
VOL. XLII. — NO. 3 3 
