202 Transactinns. — Geology. 



the Society Islands, nearly midway between them and the 

 equator, being situated between the parallels of 8° and 11° S. 

 and the meridians of 138° and 141° W. They have a warmer 

 climate than Tahiti, and are all mountainous and volcanic, 

 rising to upwards of 5,000 ft. above the sea (Magdalene, 

 3,675 ft. ; Santa Christina, 3,280 ft. ; Adams Island, 4,042 ft. ; 

 and Masse Island, 2,000 ft. high). The mountain-peaks 

 are extremely broken and rugged, and the centres of some 

 of the islands are occupied by piles of rocks of most fan- 

 tastic shape. The volcanic precipices in many places extend 

 abruptly down to the sea, presenting barren walls of black 

 and naked lava; but the intermediate valleys are singularly 

 fertile and picturesque, and are copiously watered by streams 

 which descend in numerous cascades, one of which (in 

 Nukahiva) is 2,000 ft. high, and is amongst the most beautiful 

 in the world. They have no active volcanoes, and do not 

 appear to be subject to earthquakes. 



From Angas's " Polynesia" I also extract certain remarks 

 upon active volcanoes in the Pacific ; also an extract from 

 Miss Bird's " Hawaiian Archipelago " (see Appendix A). 



I refer briefly to the Sandwich Islands. On the 24th Feb- 

 ruary, 1877, a slight shock of earthquake was felt at Kaavoloa, 

 Hawaii, and steam was observed to be rising from the sea off 

 Cocoanut Point. On visitmg the spot it was found that lumps 

 of porous lava, some nearly a cubic foot in size, were rising to 

 the surface, when, on the contained gas escaping, they sank 

 again. At the time of the earthquake a crack opened in the 

 ground from Cocoanut Point in an east -south-east direction, 

 extending for more than a mile, in some places 4 in. broad and 

 50 ft. deep. (This, again, shows the east-south-east trend. I 

 have sometimes in this paper referred to the trend as south- 

 east and north-west : I believe I should be more correct in 

 saymg east-south-east and west-north-west.) 



Mauna Haleakala, on the Island of Maui, is somewhat 

 like Mauna Kei, in Hawaii. The craters upon it are inactive, 

 the natives having no tradition of any eruption. 



Space does not permit me to refer to the phenomena in 

 the various other islands of the Sandwich Group. Oahu (on 

 which is Honolulu) is the principal island of the group, and 

 the extensive plain on which that city stands is purely vol- 

 canic. About three miles north-west of Honolulu there is a 

 remarkable circular salt-water lake, about half a mile in 

 diameter, so impregnated with salt that twice every year the 

 natives take out large quantities of fine, hard, clear, crystalUzed 

 salt, which furnishes a very valuable article of commerce. 

 At the time of the visit of the United States Exploring Ex- 

 pedition it was believed by the natives to be fathomless, but 

 on examination by Commodore Wilkes it proved to be only 



