J. D. Dana — Geological History of Oahu. 97 



levels, there are 505 feet of hard coral rock • and then on the 

 1045-foot level, a 28-foot layer of soft white coral and at a 

 greater depth, Drown clay and broken coral. As the well is 

 close by the west foot of the Head and passes through so much 

 of its tufa, it is quite certain that the 505-foot stratum of lime- 

 stone was made before the tufa-eruption ; and that the beds 

 underneath it mark earlier conditions over the site. 



As regards a supply of fresh water the well was a failure — 

 an exception to the usual experience. The water came up salt 

 and a much stronger brine than sea-water. It was under some 

 pressure, as it stood a foot above the level of surface wells 

 near by. 



Other borings have been made in Waikiki — the sea-border 

 district just west of Diamond Head. The section afforded by 

 the deepest of the Waikiki wells is here inserted for compari- 

 son. It is that of the King's well, ~No. 2 — about half a mile 

 west of Diamond Hill and 350 yards from the seashore. 



Thickness. Depth. 



Sand and coral 38 feet 



"White coral rock _ _ 22 60 



Yellow sand 43 103 



Hard lava 47 150 



White coral rock 110 260 



Blue clay 25 285 



Tough clay and coral 65 350 



Blue clay 30 380 



Hard coral rock 40 420 



Soft coral.. _. 30 450 



Tough clay — 5 455 



White coral rock 40 495 



Tough clay.. - __ 30 525 



White coral rock 100 625 



Tough clay 5 630 



Coral and clay 70 700 



Tough clay 28 728 



Black sand 2 730 



Lava 120 850 



In this well, the upper 320 feet probably correspond approx- 

 imately to the upper tufa-made portion of the preceding. It 

 is remarkable that tufa is wholly absent, although the distance 

 from the active vent was so small ; but this is accounted for 

 by the direction of the trade winds, which would have carried 

 the ejected material seaward — the direction in which the hill 

 is elongated. Moreover the tufa-cone although 1000 feet high 

 may have been thrown up in a single year or less. Instead of 

 tufa for the upper part, there are, underneath 38 feet of sand and 



Am. Jour. Sci.— Third Series, Vol. XXXVII, No. 218.— Feb., 1889. 



7 



