614 F. A. Ferret — Some Kilauean Ejeciamenta. 



Those of Vesuvius and Etna are slightly scoriaceous, which 

 accounts for their lower specific gravity. These products of 

 Pacific, Atlantic, and Mediterranean volcanoes are so similar 

 in size, form, and general appearance as to require marking 

 for identification. 



At Kilauea the ejection of these bombs and blocks took place 

 after that of the ash, in which they are imbedded to the extent 

 of about one-half of their mass. The bombs have been slightly 



Fig. 4. 



Fig. 4. Showing effect upon sand produced by impact of falling block or 

 bomb. 



deformed by the impact, which has produced, on the surface of 

 the ash field, a circular, depressed area, resembling a fish's nest, 

 in the center of which projects the comb or block, as shown 

 in fig. 4. 



In a region exposed to strong wind and torrential rains it is 

 difficult to believe that such formations could withstand a cen- 

 tury of weathering. At Stromboli, in 1912, precisely similar 

 impact depressions were obliterated by the first heavy rain, but 

 in this case the ash, newly fallen, had not become compacted, 

 and here we have an additional reason for believing the forma- 

 tion of the Kilauean ash beds to have considerably preceded 

 the ejection of the solid blocks and bombs. 



The largest of the true lava bombs found by the writer at 

 Kilauea is shown in fig. 5. It is of the turtle-back variety, of 



