VOLCANIC ASHKS AND THKIR ORIGIN 55 



cane fields are considerably higher up than the mill, where water is 

 plentiful. 



Numerous bluffs show themselves in the higher sloi)es, where large 

 blocks have been elevated unequally b}'' dynamic forces. One of these 

 elevations is the famous Hilea " butte " figured by Captain C. E. Dutton. 

 According to him, " the buttes are mere remnants of a large alluvial 

 formation which was originally continuous."* The material is certainly 

 like silt, but the theory of its eolian origin, rained down from an atmos- 

 phere charged with volcanic dust, better accommodates itself to all the 

 })henomena than that of marine accumulation. Immense " aa " flows 

 between Hilea and Naalehu destro}'' the continuity of the deposit, and it 

 underlies the fertile fields of Waiohinu and other tracts as far as to the 

 Kahuka ranch of Colonel Norris. Here the continuity has been inter- 

 rupted by the flow of 1868. There is an interesting depression in the 

 ash here, a crater-like opening a hundred feet deep and a thousand across, 

 used as a hot-house for the growth of fruits and vegetables. 



Mr J. S. Emerson states that this ash is abundant in Kona, and others 

 have observed it by the seashore near the terminus of the 1868 flow. 

 The western edge is abrupt, 10 feet thick. King Umi, who reigned eight 

 or ten centuries ago, built a road through Kona on the surface of this 

 dust ; hence we know the time of its eruption reached ver}^ far back, 

 probabl}^ before the existence of the Hawaiians on the island. The ash 

 is said to be divided in the middle by a white layer. 



The region north of Hilo contains this same bed. At the village of 

 Hilo it is exposed in a cutting by the house of Judge D. H. Hitchcock. 

 Several miles to the north it appears in the road adjacent to the shore, 

 and it is higlily probable that the long array of sugar plantations in this 

 district is underlaid by the same. In climbing Mauna Kea I found this 

 ash abundant on the south slope, especially at Puakala, more than 6,000 

 feet above the sea. It was of noticeable thickness. 



Origin of the Ashes 



As to origin of the ashes, it is evident: 



1. That they represent at least two eruptions, separated by an interval 

 of considerable duration. 



2. As the beds are alike in number on opposite sides of the island, we 

 should naturally look for their source at Mokuaweoweo, a central point, 

 rather than the neighborhood of Hilea or from Kulani, on the eastern 

 slope. 



* Fourth Ann. Rept. U. S. Geol. Survey, p. 98. 



