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CLARENCE N. FENNER 



condition the mixture exhibits the lack of coherence and readiness 

 to flow that characterize liquids. 



The exact counterpart of this deposit does not seem to have 

 been described among volcanic phenomena elsewhere, but the 

 avalanches of incandescent sand and ash that formed prominent 



Fig. II. — Specimen of banded pumice (4X4 inches) from the deposit in the 

 Valley of Ten Thousand Smokes. Adjacent bands show marked differences in 

 composition, as indicated by a silica content of 74.70 per cent in the case of a light 

 band, and 60.40 per cent in an adjacent dark band. The structure is believed to 

 be due to digestion of foreign material. 



features of the eruptions of Pelee and La Soufriere in the Antilles 

 in 1902 seem to offer many close analogies. The following quota- 

 tion from the Encyclopedia Britannica gives a statement of the 

 essential features that have been observed in the Pelean eruption: 



Its distinctive character is found in the sudden emission of a dense black 

 cloud of superheated and suffocating gases, heavily charged with incandescent 

 dust, moving with great velocity and accompanied by the discharge of immense 

 volumes of volcanic sand, which are not rained down in the normal manner, 



