J. D. Dana — Geological History of Oahu. 99 



then, underneath 109 feet of " yellow clay " which may be 

 Punchbowl tufa, 23 feet of coral rock above the 393-foot level, 

 and 107 feet of white and yellow sand below it ; with the bot- 

 tom lava at 508 feet covered by 4 feet of quicksand. An 

 abundant flow of water was obtained. 



3. South of the last, in the " Kewalo well," begun near the 

 sea-level, beneath 6 feet of black volcanic sand, there were 50 

 feet of coral rock over a 40-foot layer of hard lava ; then 190 

 feet of coral, divided in two by an intercalated 30-foot layer 

 of " clay," over the 350-foot level ; with the bottom lava-bed 

 at 620 feet. 



4. Section from a well in the Palace yard : 



Soil 4 feet, black sand 4 .'- 8 feet. — 



Coral rock 64 72 feet. 



Hard lava 6 78 



White coral rock 60 138 



Clay 240 378 



Coral rock 75 452 



Clay and gravel. 254 707 



Lava or bed rock penetrated 55 762 



Of the above sections 1, 2 and 3 have a thick bed of clay 

 on the 260-foot to 280-foot level ; 1, 2 and 4 on the 330-foot, 

 370-foot and 378-foot levels ; 1 and 2 and 3 on 460-foot, 500- 

 foot and 535-foot levels ; and No. 4, a layer 254 feet thick on 

 the 707-foot level or the bottom rock. It is possible that one 

 or more of these of "clay" maybe decomposed tufa of Punch- 

 bowl origin. But to refer all to this source would make the 

 period of eruption of very improbable length. The " black 

 sand " below the soil in Honolulu is naturally referred to this 

 source. But more investigation is required for a decision. 

 There is no evidence that Diamond Head and Punchbowl were 

 of simultaneous origin. 



5. West Oahu. — The mountains of "West Oahu cover at the 

 present time a much smaller area than those of East Oahu. 

 Their original dimensions we have no data for estimating. The 

 highest peak, Kaala, in the northeast part of the group of sum- 

 mits, has a height, according to the government survey, of 

 3586 feet; — which is 681 feet greater than that of Konahuinui ; 

 and besides this, there are, in the southeastern part, peaks of 

 3105 and 3110 feet. These elevations, and the deep and open 

 valleys divided off by sharp ridges, are sufficient evidence that 

 the mountain range is but a small remnant of the once great 

 volcanic mountain, probably a loftier mountain than that of 

 East Oahu. Denudation has had a far longer time for its dis- 

 secting work, and has done much to diminish the area it covers. 

 Whether great loss has resulted also from subsidence is not 

 ascertained. 



