ii 4 REGINALD A. DALY 



of the rising massifs probably cannot be measured, but such differ- 

 ential destruction must develop still further the rough summit-level 

 accordance already in part established by isostatic adjustment. 



4. Conclusion. — The downcrushing of higher, heavier blocks 

 with the simultaneous rise of their lower, lighter neighbors, coupled 

 with the likewise simultaneous, specially rapid loss of substance on 

 the higher summits, form a compound process leading toward a 

 single, relatively simple result. In both the architecture and the 

 sculpture of her alpine temple, Nature decrees that its new domes 

 and minarets shall not be indefinitely varied in height. Such ac- 

 cordance as they have among themselves will be preserved and 

 accentuated as her chisels fashion new details on the building. The 

 accordance of the present time in any alpine range is in part inherited 

 from what, in this paper, has been called the "original" form of the 

 range. The original form meant a first approximation to the result; 

 the later, spontaneous modification of that form means a second 

 approximation to perfect accordance. 



The composite explanation. — In passing to an analysis of erosion 

 events following the epoch of folding, we are, therefore, illustrat- 

 ing the cumulative forces of all the hypotheses so far announced 

 as alternative with, and as against, the peneplain hypothesis for 

 truly alpine ranges. By the peneplain hypothesis, the accordance 

 of summit-levels was most perfect in the initial stage of the physio- 

 graphic cycle begun by the up warping of the peneplain; by that 

 hypothesis mature dissection of the range tends to destroy some- 

 thing of the initial accordance. The alternative, composite explana- 

 tion, already in part outlined, involves the conclusion that the accord- 

 ance tends to become more and more perfect as the stage of mature 

 dissection of the newly folded range is reached. The question 

 remains whether the accordance inherited from the forms original 

 from the epoch of plication may be so much further developed by 

 subsequent erosion in the physiographic cycle initiated by that 

 plication, as to give the amount of accordance actually observed in 

 the existing range. If the answer be affirmative, the second inquiry 

 becomes imperative as to the relative merits of the peneplain and 

 composite hypotheses when applied to individual ranges. For 

 reasons given on a previous page, the second inquiry is not specially 

 raised in the present paper. 



