42 C. H. HITCHCOCK — GEOLOGY OF OAHTJ 



side. It i.s covered generally by a thick matted mass of grass, and the 

 eastern part of the crater by tree ferns. The rock is rarely exposed, 

 being a basalt very much softened by decay. The underlying rock has 

 been softened down to a clay. The depth of the basin is estimated at 

 250 feet below the rim. The immense mass of coarse black ash at the 

 base of the cone and all along the carriage road above Punchbowl make 

 it probable that it was one of the products of eruption from Tantalus. 

 Tantalus is situated upon the west slope of the Koolau range, 1,600 

 feet above the sea, and is probably only one of many others similarly 

 located in the unexplored region. It is also to be compared with the 

 source of the red-ash clinker deposit mentioned in the description of the 

 Pali phenomena and the small nameless crater a mile west from the 

 Pali summit. Being quite near Honolulu and reached by an excellent 

 carriage road with low grades, it is becoming a place of much resort for 

 pleasure and soon of residences. One of these little known craters is 

 mentioned by Brigham on page 17 of his " Notes " : 



"At the head of Punaluu valley is a large cone crater from which radiate sev- 

 eral valleys, as the Kahana, Kaliiwaa, Punaluu, and others. This crater is densely 

 wooded, and occupies nearly the center of the range. No one seems to have as- 

 cended it, and it is impossible to say how deep the cavity may be, but the internal 

 slopes as seen from below seem to be quite steep, and probably the outer wall is 

 broken down. Soft red clinkers are found in the stream at Kaliiwaa." 



PUNCHBOWL OR PJ'OWAINA 



This is a tuff cone on the edge of the city of Honolulu, and is situated 

 at the base of Koolau Poko, very nearly in the outlet of Pauoa valley. 

 It is 498 feet above the sea, and rises from the edge of a plain 40 or 50 

 feet high. The spread of the cone is just a mile. The top is 2,200 feet 

 in its longest and 1,800 feet in its shortest diameter. The depression of 

 the bowl is about 150 feet on the southeast side, and a considerable 

 chasm has been channeled out by the descending waters accumulating 

 in the basin. Good carriage roads ascend the hill from both sides, unit- 

 ing in the saddle on the northeast side at a height of 263 feet, and then 

 curving around the east side so as to pass through the lowest point in 

 the rim. It is an excellent place from which to see not only the city but 

 most of the localities of geological interest. Most of the year the sides 

 of Punchbowl are covered by scanty, parched vegetation, as there is no 

 reason for its irrigation. The rock is tuff, with a resinous luster or 

 palagonite. Being frequently yellowish brown in color, Professor Dana 

 says the color is evidence that the temperature of the water was below 

 200 degrees Fahrenheit when the beds were deposited. The structure 

 is clearly that of the normal volcanic cone, the strata dipping quaqua- 



