88 J. D. Dana — Geological History of Maui. 



this Journal for November last,* and have afforded unex- 

 pected evidence on the.°e doubtful points. They have led him 

 to the important conclusion that " the density of the moun- 

 tain is at least equal to its surface density," and that, therefore, 

 unlike some results obtained on the continents, " it is a solid 

 mountain," so that the interior must have been left filled by 

 the subsidence of rock that made the great crater at the sum- 

 mit. He states also that " the zenith telescope observations at 

 the foot of the mountain indicate the same fact." 



Mr. Preston states further that at Kohala, on the north coast 

 of the island Hawaii, the plumb-line deflections were half a 

 minute southward, which, he adds, is well explained by the po- 

 sition to the southward of all the great mountains of Hawaii. 

 He records also that at Hilo, on the east coast, the deflection was 

 a fourth of a minute to the northward. Mr. Preston remarks 

 that " there is no explanation " of this result at Hilo " unless 

 we assume that the south side of Hawaii, where the volcanoes 

 are active, is much less dense than the north side where the 

 fires have been slumbering for centuries." But to the north 

 of Hilo is a long reach of ocean, the coast of Hawaii there 

 trending northwest ; the summit of Mt. Kea, 13,805 feet high, 

 is 25 miles distant and bears 1ST. 75° W. ; and that of Mt Loa, 

 13,675 feet high, is 35 miles distant and bears S. 63° W.; 

 and the center of gravity of the combined mass (the lowest 

 level over 5000 feet) bears probably a little south of due west. 

 It appears, hence, that we have here evidence that Kea is like 

 Loa, not solid ; that it is a hollow mountain, as inferred above 

 from the absence of a summit crater ; but Mr. Preston is prob- 

 ably right in his inference that Mt. Loa is the more cavernous 

 of the two. Additional plumb-line and pendulum observations 

 are, however, much to be desired. 



2. West Maui. 



"West Maui has lost the original slopes of its great cone and 

 its crater through erosion. It has been supposed that remains 

 of three great craters may be distinguished in the mountains : 

 the largest at the head of Wailuku or Iao valley on the north 

 border of which rises the highest peak, Puu Kukui, 5788 feet 

 high ; another in the less deep valley of Waihee, just north of 

 this ; and a third at the head of the Olowaiu valley, to the 

 south. 



I examined only the "Wailuku valley, the largest of the three, 

 — so named from the village on the coast near its entrance. 

 The valley is a deep cut into the mountains, remarkably grand 

 in its precipitous walls with thin crested summits. It widens 



* Vol. xxx vi, 305. 



