Branner — Geology of the Hawaiian Islands. 301 



Aet. XXIX. — Notes on the Geology of the Hawaiian Islands ; 

 bj J. C. Branner. (With Plate XY.) 



Introduction. — The few notes I was able to make during a 

 recent visit to Haw^aii are necessarily fragmentary, but our 

 knowledge of the geology of these islands is so strictly confined 

 to volcanic phenomena that I venture to publish these facts 

 for what they are worth. 



It is much to be hoped that the territory will make early 

 provision for a geological study of the group. A modest terri- 

 torial survey could be readily and cheaply carried on in con- 

 nection with either the government survey or with the Bishop 

 Museum at Honolulu. Such a survey could bring together 

 illustrative material of the greatest scientific importance and 

 educational value, and it would reflect great credit upon the 

 intelligence of the people of the islands. 



The canyons on the north side of Hawaii. — One of the 

 most striking features of the island of Hawaii is the series of 

 canyons on the northern coast of the island. These gorges are 

 mentioned by Dutton,^ but he says nothing further of them 

 than that they are valleys of erosion. 



One of the most striking things about them is that as one 

 sails round the extreme north end of the island the coast bluffs 

 are low— averaging less than a hundred feet — and the land but 

 little broken and under cultivation. Suddenly there is an 

 abrupt change in the coast topography : the bluffs facing the 

 area have an elevation of a thousand feet, and enormous gorges 

 extend inland with almost perpendicular walls, some of which 

 it is said are as nmch as 2,000 feet in height. These gorges, 

 great and small, continue for twelve miles along the coast, 

 where they end as suddenly as they began, against compara- 

 tively smooth arable lands. The region of gorges is covered 

 with forests, and, save in the flat valleys, is not cultivated. 

 The gorges extend back inland for five or six miles, in the 

 direction of the cluster of highlands near Waimea Yillage. 

 The summit of this cluster is reported to be 5,505 feet high. 

 One of the remarkable features of these valleys is the fact that 

 they are nearly or quite as deep at or near their upper ends as 

 they are at their lower ends. Another striking feature is that 

 the largest of them have flat bottoms. 



This deeply eroded part receives no more rain than the 

 adjacent areas north and south of it, and the ditference in 

 topography is due, I believe, to the difference in age between 



*^ Hawaiian Volcanoes. By C. E. Button, Fourth Ann. Report TJ. S. 

 Geological Survey, 1882-83, pp. 75-219. Washington, 1884. 



Am. Jour. Scl— Fourth Series, Vol. XVI, No. 94.— October, 1903. 



