20 Vol. XLIlL, Art. 6. — s. Tsiiboi: 



by éjecta of later eruptions and are not yet dissected so that, 

 practically nothing is known of their geologic structure and re- 

 lationship to the main body of the somma. Three of the above, 

 however, — the middle hill of Mitsumine^^ (la), Futago'^ (2d), and 

 Takenohira'^-' (2e) — appear to be built up of scoria? consisting of 

 glass with some plagioclase phenocrysts. 



Other knobs are entirely covered by later éjecta so that it is- 

 not evident of what they are composed ; but it may not be un- 

 reasonable to suppose that they are also constructed of scoria? 

 seeing they resemble the above three in morphographic features, 

 as well as in other respects. 



Mention has already been made (pp. 17-18) of the formation 

 of spatter cones by the accumulation of scoriaceous lapilli on the 

 lava surface. It is not impossible that the knobs now under con- 

 sideration originated in the same way as those spatter cones. 

 Bat, so far as observed, the lavas are generally on too small a 

 scale to account for such a comparatively large quantity of scoriae 

 as would be contained in these knobs. 



On the other hand, some of the somma lavas are considered 

 to liave been discharged as effluent flows from flank openings 

 though the location of these cannot be pointed out at present. It 

 is possible that seoriee would have accumulated on some of these 

 openings from which the lava flows were extruded. As a matter 

 of fact, it was actually observed in the central crater of Miliara^-*' 

 (2c) on the eruptions in 1876-77 and in 19 12-' 14, that a largo 

 quantity of scoriao was spattered out from the vents through which 

 the lavas w^ere issuing. 



The parasitic knobs on the flanks of the somma are considered 

 to have been formed in this way by the accumulation of scoriae 



1) H* 2) -^ 3j ig-zifi 4) ELW. 



