DEVELOPMENT OF PILLOW-LIKE FORMS 645 



Samoan Islands (plate 23, figure 2). Where a vigorous flow of lava was 

 entering the sea explosions were almost continuous, and the place was 

 obscured by clouds of steam, from which fragments of red-hot lava and 

 showers of black sand were projected. 



"Where the lava was flowing in smaller quantity explosions were much less 

 noticeable and the lava extended itself into buds or lobes. The process was 

 as follows: an ovoid mass of lava still in communication with its source of 

 supply and having its surfaces, though still red-hot, reduced to a pasty con- 

 dition by cooling, would be seen to swell or crack into a sort of bud with a 

 narrow neck like a prickly pear on a cactus, and this would rapidly increase 

 in heat, mobility, and size till it either became a lobe as large as a sack or 

 pillow, like the others, or perhaps stopped short at the size of an Indian club 

 or large Florence flask. Sometimes the neck supplying a new lobe would be 

 several feet long and as thick as a man's arm before it expanded into a 

 full-sized lobe ; more commonly it would be shorter, so that the freshly formed 

 lobes would be heaped together. They looked white-hot, even in daylight, and 

 as the waves washed over them the water seemed to fall off unaltered with- 

 out boiling, owing probably to its being in the spheroidal condition." 



Plate 23, figure 2, which is a copy of Anderson's plate lii, is a view 

 from the lagoon near Seleaula. The lava in the background has cooled 

 slowly and assumed the usual corded structure. In the foreground many 

 of the lobes have flowed into the water and been chilled before they had 

 time to do this.^^^ 



Dr. Arthur L. Day, Director of the Geophysical Laboratory, has kindly 

 permitted me to use the accompanying photographs (plates 22 and 23) 

 of newly formed pillows at the crater of Kilauea. Dr. Day writes in ex- 

 planation: "The print which shows us collecting gases (plate 22, figure 

 1) was made within a few feet of the liquid lava lake, and the pillows 

 which it contains formed in plain view three days before the picture was 

 taken. The manner of formation, I think, is precisely described in the 

 manuscript which you showed me some time ago." The reference here 

 is to brief manuscript notes that were used in presenting an outline of 

 this paper before the Society on December 30, 1913, embodying in outline 

 the theory of the pillows that is given somewhat more fully in the fol- 

 lowing paragraphs . 



139 See also Geogr. Jour., vol. xxxix, 1912, pp. 123-132, and Kept. Brit. Asso. Adv. Sci. 

 Sheffield meeting, 1910, p. 654. 



