512 



WHITMAN CROSS 



three miles, is a very clearly defined bench or terrace with abrupt 

 western border and northern end. A small point on its surface gives 

 the name Puu Anahulu. This bench is indicated on the map by the 

 hachures marking its steep western slope. 



On the south the terrace of Puu Anahulu merges with the low 

 grade slopes of Mount Hualalai and on the east with the surface of 

 still smaller angle down which lava flows have come from Mauna 

 Loa, some thirty miles away. Some of the late flows from Mount 

 Hualalai have spread over the terrace, and in places have fallen in a 

 stony cascade down the steep western bank. Others from the same 

 source have passed between the terrace and the cone of Puu Waawaa. 

 Some from Mauna Loa have also poured over portions of the bench 

 or passed around its northern end to the sea. Puu Waawaa has been 

 encircled by lavas from Hualalai which have cut it off from the 

 terrace. 



The terrace bench of Puu Anahulu is made up, so far as obser- 

 vations go, of an agglomeratic aggregate of large and small fragments 

 of the rock to be described. In general, this rock is much decom- 

 posed by kaohnization, only the larger fragments still consisting in 

 part of dark gray material. The softer, light-colored rock has been 

 used for road metal on the new government road from Waimea to 

 Kona, which passes over this bench. Both the bleached and the 

 darker rock exhibit a rude schistosity due to a parallel arrangement 

 of minute feldspar tablets, like that common in phonolite and in some 

 trachytes. 



Puu Waawaa is scored by numerous radial ravines penetrating its 

 slopes for fifty feet or more, and in all of them examined the typical 

 structure of a tuff cone is revealed.- The cone seems to be made up 

 of tuffs of varying texture, well stratified, and dipping nearly with the 

 slope of the cone. Most of the tuff is made up of ash or fine gravel, 

 with angular fragments irregularly distributed through it, which 

 rarely exceed a few inches in diameter. 



The fragments consist of brown pumice, dark aphanitic, or black 

 obsidian-like rocks, with some showing a mingling of the latter 

 materials. The dark aphanitic fragments are not unlike some dense 

 basalts of the island in appearance, yet resemble also the freshest 

 rock from the bowlders of Puu Anahulu. 



