8. Powers — Explosive Ejectamenta of Kilauea. 241 



source of the Kahuku flow and reported that the ground was 

 covered for a distance of 10 miles from the crater with basaltic 

 pumice stone.* Dr. William Hillebrancl visited the same 

 locality a few days later and also reported the pumice.f In 

 1880 Dr. W. T. Brigham ascended Mauna Loa and reported 

 that the summit plain for acres was covered with thread lace 

 scoria similar to that at Kilauea, which he describes as " froth 

 of the burning lake.":}: Thread-lace scoria has probably not 

 been formed in any of the eruptions since 1868. 



From the above it will be seen that the thread-lace scoria 

 may be formed during the eruption of lava from the main 

 crater from which the lava issues, aiid that it may be blown 

 over great distances. Also, judging from the description by 

 Green, the thread-lace scoria represents the glassy, gaseous 

 froth of the lava. 



Other Ash Dej^osits. 



On the island of Hawaii deposits of ash are also found in 

 small quantities on the Kohala Mountains, on Hualalai ; and in 

 large quantities on the slopes of Mauna Kea and in the region 

 of the Mohokea " crater," northwest of Pahala, stretching 

 from Kaalualu to Kapapala. In the first two localities the 

 ash is confined to the vicinity of the summit and lateral cones 

 and cone-craters, and therefore needs no further description. 



The closing stages of activity of Mauna Kea were marked 

 by the development of large ash cones which completely bury 

 the bed-rock summit of the mountain, thereby making it 200 

 feet higher than Mauna Loa. The ash deposits envelop the 

 mountain, where they have not been removed by subsequent 

 erosion, and on the ash-covered slopes near the sea on the 

 eastern side are the sugar-cane plantations of Hamakua and of 

 North and South Hilo. At Hilo the ash disappears beneath 

 the younger lava flows from Mauna Loa. A short distance 

 north of the lower iron bridge at Hilo over 5 feet of ash is 

 exposed ; near Papaikou 20 feet of ash is seen overlying aa 

 lava ; at the shore at Pepeekeo 40 feet of ash overlies the 

 basalt ; at Paauilo less than a foot of ash is seen near the rail- 

 road ; at Weha, near Paauhau, a three-inch vertical fissure in 

 aa has been filled with ash which is about 4 feet thick on the 

 surface ; at Honokaa the ash is 3 to 5 feet thick ; on the 

 Waimea plateau at an elevation of about 2700 feet the ash is 

 2 to 3 feet thick. On the west side of Mauna Kea the ash is 

 also seen, and at Keamuku gulch it is 3 feet thick. South of 

 this point, however, it is concealed by younger flows from 

 Mauna Loa and Hualalai. 



*Idem, p. 105. 

 f Idem, p. 111. 

 \ Mem, pp. 20, 144, 92. 



