THE MOUNTAIN FKONT 209 



If the original uplift of the mountain mass ever produced a great 

 fault cliff, all traces of it are now destroyed by erosion ; for the moun- 

 tain front is today elaborately carved into a succession of huge buttress- 

 ing spurs separated by great ravines. The stream lines of the ravines, 

 dry at the time of my visits, are, as a rule, unbroken by a sharp descent 

 over rock ledges. The ravine floors are for the most part strewn with 

 waste derived from the converging slopes — that is, the intermittent 

 streams of the ravines have generally reached a graded condition, their 

 slope being just about sufficient to give a carrying power that enables 

 them to deal with the waste that is washed down from above and from 

 either side. Only near the head of the ravines, where the process of 

 grading would be latest completed, are strong ledges and cliffs still bare. 



The slopes of the buttressing spurs are also generally well graded in 

 their middle and lower parts to an even angle of descent, and thinly 

 veneered with waste. Olive orchards are cultivated on the lower slopes. 

 It is true that some of the more resistant beds of the nearly horizontal 

 limestones may be traced in more or less continuous outcrops, contour- 

 ing forward around the buttresses and turning back into the great ravines ; 

 but the ledges thus determined are not strong enough to break the 

 general impression of even descent that characterizes the slopes. The 

 front base of each buttress is more or less distinctly truncated by a 

 triangular facet, also of generally graded slope, leaning back from the 

 vertical at about the same inclination as that of the sloping sides of the 

 ravines. The slope of the ravine floors is much less steep than that of 

 the sides ; yet their descent is by no means gentle. Taken altogether, 

 the carving of the ravines and buttresses to their existing form means 

 long and patient erosive work, persistently acting with respect to some 

 well maintained piedmont baselevel, a work that must have reached 

 the satisfactory condition of established grades first in the lower parts 

 of the ravines, later in their higher parts, and still later on the tribu- 

 tary slopes of the spurs. If any depressions had originally existed in 

 the piedmont part of the drainage ways, they must have long ago been 

 aggraded by the plentiful waste that has been discharged from the 

 ravines. Continuity of graded descent with decreasing declivity for- 

 ward from the mountain front should therefore be an assured accom- 

 paniment of the normal, undisturbed conditions indicated by the well 

 graded forms of the carved mountain front. 



The Rock Fans 



A cross-section of any one of the ravines in its middle course shows 

 a V-shaped profile, somewhat rounded at the lower angle; but near the 



