318 E.Howe — Tuffs of the Soitfriere^ Si. Vincent. 



The devastated area has been admirably described by various 

 writers, notabl}' Drs. Anderson and Flett, in their report to 

 the Eoyal Society,"^ and Dr. E. O. Hovey,t and a further 

 description would involve unnecessary repetition. 



The bolder forms of the consequent drainage which had 

 been developed on the slopes of the Soufri^re have been little 

 changed as a result of the recent eruptions. Changes that 

 have taken place are due less to the new material thrown out 

 than to the abnormal erosion resulting from thfe complete 

 removal of vegetation and the unusually heavy rains following 

 eruptions. The effects of this erosion are naturally best 

 observed in the areas adjoining the larger streams near their 

 mouths. Directly after the great eruptions the valleys of the 

 Wallibou and Rozeau Dry rivers were almost completely filled 

 in their lower portions with the ejected material from the 

 Soufriere, and about a mile back from the coast these accumu- 

 lations were nearly a hundred feet in depth, according to the 

 accounts of many who saw them soon after the eruptions, and 

 my own observations some months later confirmed these esti- 

 mates. From the regions of maximum accumulation there was 

 a gradual decrease in thickness towards the mouths of the 

 rivers, where landslides occurred, leaving cliffs of the older 

 and younger tuffs not more than 20 feet high. The old drain- 

 age systems were still sufficiently well marked to direct the 

 new streams that were at once formed, and these began 

 actively to attack the new deposits, with the result that at the 

 time of my visit there had been developed a miniature system 

 of canyons which showed in their nearly vertical walls excel- 

 lent sections of recent deposits. 



Recent deposits. — The ejecta of the recent eruptions now 

 occur in formations of three distinct types, with characters 

 directly related to their modes of origin. The composition of 

 all of them is essentially the same and corresponds closely to 

 that of some of the larger ejected blocks, which appear to be 

 basalts, rich in plagioclase. The material varies from the finest 

 powder to blocks of massive rock several feet in diameter, the 

 most abundant being a coarse sand in which broken crystals of 

 plagioclase, augite and a little hornblende may be distinguished. 

 In the great eruption of September considerable pumice was 

 thrown out, hardly any of which is to be found in the earlier 

 deposits. 



The most conspicuous deposits and* probably the oldest are 



*Preliminary Eeport on the Eecent Eruption of the Soufriere in St. Vin- 

 cent, and of a visit to Mount Pelee, in Martinique. Proc. Eoyal Soc, vol. 

 70, pp. 423-445. London, 1902. 



f Martinique and St. Vincent : A Preliminary Eeport upon the Eruptions 

 of 1902. Bull. Am. Mus. Nat. Hist., vol. xvi, Art. 26, pp. 333-372, 1902. 

 This Journal (4) xiv, 319-359. 



