J. D. Dana — Geological History of Maui. 87 



The evidence that the lavas were discharged in both direc- 

 tions at once at the last eruption consists in the nearly uni- 

 form appearance of the fresh lavas over the bottom of the crater 

 from one end to the other, and their continuing into and ap- 

 parently being the streams that descend the Kaupo and 

 Koolau discharge-ways. Mr. J. M. Alexander has remarked 

 that the crater is probably a double one, a combination of two 

 great craters, as Mokuaweoweo at the summit of Mt. Loa is 

 compound in structure. This is no doubt historically true; 

 but at the latest of the eruptions there was probably one ac- 

 tion over the whole!; the distinction for the time obliterated. 



The period of the last summit eruption is unknown. I learn 

 from Mr. Bailey of Wailuku, Maui, that, according to an 

 island tradition, a lateral eruption of the mountain occurred 

 about 150 years since in the district of Honuaaula of the 

 southern part of East Maui, at an elevation above the sea 

 probably of about 400 feet. 



6. Activity of the Crater ending in Cinder-ejections. — The 

 origin of the crater of Haleakala needs, I believe, no explana- 

 tion beyond that given in the remarks on the origin of craters 

 generally : that a volcanic crater and the mountain containing 

 it commence to form together about an opened vent which 

 discharges both vapors and lavas ; that the crater is a result of 

 the projectile action and the discharge of material from below, 

 and generally also of subsidence into the cavity which is made 

 by the discharge ; and that it does not become closed before 

 the central vent ceases to discharge, and commonly is not then 

 closed.* 



Haleakala is an example of a basaltic volcano which reached 

 its end, through declining fires, in cinder ejections ; but it left 

 its great crater open, and 2000 to 2500 feet deep, with the 

 greater part of the bottom free from the cinders notwith- 

 standing the amount discharged. The latest down-plunge or 

 subsidence by which the vast pit and perhaps also its dis- 

 charge-ways were made, may therefore have filled full the 

 empty subterranean chambers which former outflows had pro- 

 duced, and left the mountain solid instead of hollow. Mt. 

 Kea on Hawaii, 13,805 feet in height, also ended its work with 

 cinder eruptions ; but the ejected material of lavas and cinders 

 obliterated so far the old crater that no visitor of the region 

 has yet found traces of its former limits. Whether Mt. Kea 

 is a hollow mountain or not remains to be ascertained. 



Since the above was written, the results of the pendulum in- 

 vestigations of Mr. E. D. Preston at the summit of Haleakala 

 have been made known in a paper published in the number of 



* This J., xxxv, 33, Jan. 1888. The view is the same published in my Explor- 

 ing Expedition Report, 40 years since. 



