2 PJiysko-Geognostk Sketch of the Island qfOahu, 



these two points, forms an angle of 58° with the meridian, and 

 is more obtuse than the line of direction of the two chief groups 

 of mountains. The largest portion of the island is situate to the 

 north-east of the above line, not much more than a third being 

 to the south-west. The mountain groups are situate one on 

 each side of the line. The extreme breadth of the island is 

 from Kahuku on the north, to Laaloa (Barker's Point) on the 

 south, twenty-eight miles. The line joining these two points 

 forms an angle of 26° with the meridian, and of 85° with the 

 extreme longitudinal line. About four-fifths of the island are 

 to the east of the line, and only one-fifth to the west of it. 



The general form is that of an irregular quadrilateral figure, 

 the longest side being directed to the north-east, and extending 

 from Kdko to Kahuku in a straight line thirty-seven miles. The 

 second regards the S. S. W., and extends from Koko on the east 

 to Laaloa on the west, thirty-four miles in a straight line. The 

 third, which regards the W. S. W., extends from Laaloa on the 

 south to Kaena on the north, eighteen and three quarter miles. 

 The fourth and last, regarding the north-west, extends from 

 Kaena on the west, to Kahuku on the east, eighteen and a-half 

 miles. 



I had no opportunity of visiting the eastern portion of the is- 

 land to the east of a line joining Kailua on the north with Leahi 

 (Diamond-pt) on the south, except the cursory view from the 

 ship in coasting it on our arrival at the island. 



There are two principal chains or groups of mountains. The 

 easternmost and most extensive, to which I shall give the name 

 Ronahuanui, from its highest summit extends in a direction 

 nearly parallel with the north-east side of the island. I examined 

 it from Ronahuanui on the south-east, to its termination in the 

 sea, near the point of Kahuku. It probably also terminates in 

 the sea to the east at Koko, as at sea I saw a ridge extend- 

 ing from the lofty summits down to this point. It may strictly 

 be denominated a chain consisting of a series of denticulated 

 summits, separated from each other by precipitous parts or 

 passes. The most elevated part of the chain is confined to a 

 limited portion of its extent in length, about twelve miles from 

 Ronahuanui to the mountains of Kualoa ; to the north-west of 

 the latter the summits decrease much and suddenly in altitude 



