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PACIFIC SCIENCE, Vol. IX, July, 1955 
Fig. 2. Profile of the crest of the Koolau Range, with threefold vertical exaggeration. 
The differences between these four areas 
are what would be expected if the south- 
eastern end is the older and has thus been 
longer subjected to erosion. There is, of 
course, the additional difference that the high 
cliffs of the southeastern part may well be a 
strongly receded fault scarp. 
THE SUMMIT REGION 
The Crestline 
The southeastern part of the Crestline of 
the Koolau Range is deeply indented at the 
heads of the valleys that drain the leeward 
slopes, especially Manoa, Nuuanu, and Kalihi 
valleys (Figs. 2, 3, and 6b). The deep valleys 
and the deep indentations of the Crestline 
imply prolonged erosion. In the five miles 
from Mt. Olympus to the head of Kalihi 
Valley, the Crestline ranges from about 1,200 
feet to 3,150 feet in altitude, a range of nearly 
2,000 feet. 
In contrast, the northwestern part of the 
Crestline is only slightly indented (Figs. 2 and 
4) . No five-mile stretch of the Crestline would 
range more than 1,000 feet, and perhaps no 
more than 500 feet in altitude. One infers that 
not enough time has elapsed, since construc- 
tional volcanic activity ceased, for streams to 
have worked headward so as to indent the 
Crestline deeply. 
The contrast in degree of indentation would 
be a normal consequence and indication of 
greater age of the southeastern end of the 
Koolau Range with its much deeper indenta- 
tions of the Crestline. 
Areal Extent above 1,000 and Above 2,000 Feet 
Altitudes over 3,000 feet are found in the 
Koolau Range only on Konahuanui (Fig. 2) 
