210 S. Powers — Explosive Ejectamenta of Kilauea. 



period of repose, explosions renewed the activity. ~No Kilauean 

 lava flows are found on top of the summit ash, but that state 

 of affairs can be accounted for both by the lack of any evidence 

 concerning the possibility of flows near the crater and by the 

 possibility that the sink was in process of formation at the 

 time of the eruption so that lava could no longer run over the 

 edge. 



Formation of Thread- Lace Scoria. 



The origin of the thread-lace scoria is involved in what pre- 

 cedes as, if it were understood, conditions in the past could be 

 interpreted with greater certainty. It has recently been 

 asserted that "all the material observed by the writer (Perret) 

 lay upon the pahoehoe lava in a continuous stratum, indicating 

 formation in situ and therefore not to be included under the 

 head of ejectamenta."* A review of the field evidence and of 

 the literature leads the present writer to a different conclusion. 



In the first place, the thread-lace scoria is found in a con- 

 tinuous stratum, so far as can be traced, from the Keamoku 

 flow on the road to Kau to the Crater Hotel and probably 

 farther along the road to Keanakakoi — a proven distance of 

 5 miles. The underlying pahoehoe flows at the places 

 observed are only a foot or two in thickness and no single flow 

 coming from the original summit of Kilauea ever poured over 

 such an arc. Also, as shown above, there is an abundance of 

 thread-lace scoria around Kilauea not overlying pahoehoe. 



An examination of the literature shows that the thread-lace 

 scoria was formed in the Manna Loa outbreaks of 1852, 1858, 

 and 1868. In 1852 Eev. Titus Coan visited the source of the 

 flow of that year and found the pumice to be 5 to 10 feet 

 thick in the vicinity of the cone from which the lava had 

 issued, and to extend for a distance of 10 miles from the cone.f 

 The source of the 1859 flow was visited during the eruption by 

 W. L. Green, who writes : " At the lower side of the crater . . . 

 we observed some vitrified breakers. The molten glass-foam 

 had run over the lip of the crater in great waves and now stood 

 on the gentle slope below like petrified combers on the sea- 

 shore. The material of the waves seemed to be identical in 

 composition and color with the usual Hawaiian pumice or glass 

 foam, and the semi-transparent glaze covered the whole outer 

 surface.";}: J. M. Alexander reported the thread-lace scoria 

 and Pele's hair from the same eruption when he ascended 

 Mauna Loa in 1885.§ In 1868 H. M. Whitney visited the 



*F. A. Perret. op. cit., p. 617. 



f The original references will be found in W. T. Brigharn's The Volcanoes 

 of Kilauea and Manna Loa, pp. 67-8. 

 \ Idem. p. 79. 

 § Idem. p. 160. 



