OF THE HAWAIIAN ISLANDS. 433 



9. North-eastern Hawaii, Mauna Kea. 



10. Lanai, Kahoolawe. 



11. Eastern Maui, Mauna Haleakala. 



12. Western Hawaii, Mauna Hualalai. 



13. Eastern Hawaii, Mauna Loa, which with Kilauea is still burning. 

 These have been arranged in both lists in accordance with the extent of degradation ex- 



hibited, and they comprise the whole series of volcanic vents which have formed the group. 

 Niihau, I believe to have been a portion of Napali on Kauai, and Kahoolawe and Molokini 

 are but subordinate coast craters, or possibly the former is a portion of Lanai. 



Kauai. — In describing Kauai, I mentioned the remarkable similarity in structure and 

 appearance, between the western precipice of Napali and the eastern cliffs of Niihau. The 

 strata, so far as examined, correspond, and I cannot but consider the two islands parts of the 

 same. 1 Some vast disruptive force has torn it from its original position and moved it twenty 

 miles without any considerable disturbance of its strata. I own that the force seems improb- 

 ably great, but we know that Haleakala, a mountain of much greater bulk, was rent asunder, 

 and a segment moved more than two miles, and even greater breaks are supposed to have 

 occurred on Oahu. 



The history of the Kauai group I suppose to have been this : The original vents from 

 two centres of action poured forth their lava until two mountains were formed in close prox- 

 imity ; the double axis of Oahu, Molokai, and Maui, was here also, but instead of ceasing to 

 eject lava when the mountains were completed, there succeeded a period of intense activity, 

 — possibly prior to the formation of a new vent on some of the other islands, — the moun- 

 tains were broken up forming the ridges of Maunas Kalalea, Nounou, Kapu, and the Koloa 

 Ridge, — a. gigantic Somina, — while the lavas again piled up two mountains on the ruins, 

 the eastern one being the larger, as on the other biaxial islands. This will be rendered 

 clearer by reference to the diagram, which is drawn in proportion. The line a d in No. I. 

 will represent the base of the 



two mountains as originally ^^ ^ ^ -, 



formed, while xx will denote 

 the lava ducts. No. II. is a 

 section of the island after the 

 first mountains have been 

 broken up and the shore ^^ 

 ridges formed ; and No. III. i 

 is the present section, l rep- 

 resenting the coast of Napali, and n that of Niihau. In the second section the base line a d 

 is represented as equalling that at present plus the distance l a which is the breadth of 

 Niihau. The circumference has increased but little since the shore ridges were formed. 



The strata of these shore ridges all exhibit a dip towards the sea from the mountain, ex- 

 ceeding that of Waialeale, and are undoubtedly older, as lava beds from the latter have 

 penetrated their cracks. Dykes occur in the ridges in various places, always radial from the 



1 Tbe natives have a tradition that two of their gods were the pods pulled so hard as to drag Niihau some distance before 

 once fishing on the two extremes of Oahu, and that their lines the lines broke, 

 and hooks became entangled on the west coast of Kauai, and 



MEMOIRS BO»T. SOC. NAT. BIST. Vol. I. Pt. 3. 110 



L 

 Fig. 46. Theoretical Section of Kauai. 



