K Howe— Tuffs of the Soufriere, St. Viiiceiit. 321 



ridges, along the coast, an interesting structure is brought out. 

 De]30sits of the second kind, following as thej do the rolling 

 surfaces of the ridges and sides of the spurs, appear to have 

 been compressed into a series of anticlinal folds. Precisely 

 this structure occurs in the sea-cliffs about one mile south of 

 Basse Terre, Guadeloupe, where the unconformable relations 

 with the underlying beds are obscured and the pseudo-folding 

 most perfect and deceptive. 



Mode of Origin. — Whatever interest the deposits may have 

 depends very largely upon their mode of origin, and in regard 

 to this there is considerable trustworthy information. 



The events attending the fii'st eruption of the Soufriere, as 

 reported by eye-witnesses, may be briefly summarized as 

 follows : 



On Wednesday, May 7, 1902, explosions occurred and vast 

 clouds of steam rose from the Soufriere, but no damage was 

 done, and only a film of fine dust was noticed on the leaves of 

 the trees on the lower slopes. Almost at the same time, streams 

 such as the Wallibou and Eabaka became raging torrents of 

 hot, muddy water, probably due to the overflow of crater 

 lake. According to information which I received from several 

 persons who witnessed the eruptions, no mud-flows occurred, 

 and I could find no evidence in the deposits themselves to 

 show that they had descended directly from the crater as mud 

 streams. Doubtless these torrents scoured their stream-beds 

 clean, and possibly removed a little soil and vegetation, but 

 brought about no marked changes. It was not until the early 

 afternoon of this same day that the eruptions reached destruc- 

 tive violence, when an enormous black cloud, " laden with hot 

 dust, swept with terrific velocity down the mountain-side, 

 burying the country in hot sand, suffocating and burning all 

 living creatures in its path, and devouring the rich vegetation 

 of the hill with one burning blast."^ Although added to by 

 subsequent violent eruptions, it was at this time that the great 

 tuff beds in the valleys were formed. The exact nature of 

 this " down-blast " may not be clearly understood as yet, 

 but the fact of its occurrence in St. Vincent and of a similar 

 one in Martinique cannot be questioned. Briefly, its effect 

 was to sweep the ridges clean and to fill the ravines and valleys 

 with the enormous quantities of hot dust and lapilli with which 

 it was charged, in the same way that dejDressions and spots 

 protected from the wind are filled with great drifts of snow by 

 a driving storm. Deep deposits did not occur in the upper 

 portions of the ravines, since they radiated from the crater and 

 lay directly in the line of the blast, which could sweep them 



*Anderson and Flett, op. cit., p. 427. 



