114 XATLKAL HISTORY OF HAWAII. 



an.l liiid tli.-ir outlet to the oee.-iii lluoii-h the L-reat Pearl Lochs already men- 

 tioned. 



The windward side sliows plainly the full force of drenching rains -^ and 

 the cutting winds. Tor the seaward surfaces are everywhere deeply eroded and 

 the disinteural rd lava removed, leaving a series of amphitheaters, narrow 

 l>i-nninntory-like outlying ridges and clitt's that mark the more resistant cores of 



the solid rock. 



The erosion of the Kaala dome is not so easily understood since the greater 

 excavations are on the west side, while the slopes which are to windward, that 

 is towards the Koolau range, are more gradual. But as the Waianae Moun- 

 tains are conceded to l;e much older than the opposite range it is presumed that 

 the conditions wliicii exist now are much modified from those that were in effect 

 when the AVaianae Range was first eaten down. 



Smat.lkr Ijasai.tic Ckaters and Tuff-Cones. 



While the main ranges already discussed are of first importance in the 

 topograi)hy of the island, the later volcanic manifestations, especially of the series 

 of basaltic craters and tuff-cones that mark the close of volcanic activity on 

 Oahu. form striking objects in the general contour of the island. 



The tuft'-eones are the most numerous and conspicuous, several being in view 

 from llonolidu. Of these Diamond Head, or Leahi, the famous landmark often 

 spoken of as the sphynx of the Pacific, is the most noticeable. As the traveler 

 approaelies tile island for the first time Diamond Head with its imposing, rugged 

 outline is sui'e til attract attention; often, too, it is the last parting glimpse oi 

 Diamond Head from the distance, as the voyager leaves the island behind, that 

 brings the full i-ealization to mind of all that it typifies of the life in a tropic 

 land that has so fascinated him that, wander wlun'e he will, Oahu's shores seem 

 always to call liim back again. 



Diamond Head. 



Diamond Head rises in bold relief from the shore-line beyond Waikiki, to 

 the lieiLilit of 7()1 feet. While its sharp outline may seem to suggest to some the 

 ajipi-opriate and accepted popular name by which the point is known far and 

 wide, the name was, in fact, derived from the excitement created through the 

 discovery by sailors at an early day of small calcite crystals '^ that they thought 

 to be diamonds. 



This cratei" mountain looks from the outside to be solid rock, but in 

 reality it is a great hollow oval tuff-cone, 4,000 by 3,300 feet in its diameters, 

 with its elongation in the direction of the trade winds. Owing to the ejecta 

 being carried hy the prevailing winds when the crater was in eruption the 

 southwest side of this and of similar cones on the island is considerably higher 

 than is the opposite side. Inside the crater the walls slope gently to the center, 

 w^here, near the eastern wall, during the wet season, there is, or at least there 



■"■ 'llip annual rainfall at the Pali usually exceeds 150 inches. « Sfju f,, )jp ],,,(i ,-,„. ,1,^ gathering. 



