320 E. Tloioe — Tuffs of the Soufriere, St. Vincent 



inej, would accumulate more and more of the fine material, 

 until, on reachino^ the ground, tliey would be in the form of 

 hard clay pellets. When I visited the crater, such drops, 

 although much diluted, were falling almost continuously, fol- 

 lowing the small intermittent eruptions of steam and mud that 

 were taking place from time to time. Flett and Anderson 

 make reference to the same phenomenon in speaking of the 

 Soufriere. They say : '' Before midday there had been very 

 heavy rain-showers, and it was noticed that the rain-drops car- 

 ried down fine particles of ash."^ And again, in describing 

 the eruption of Pelee, which they witnessed : " In a minute or 

 two fine, grey ash, moist and clinging together in small glob- 

 ules, poured down upon us. After that for some time there 

 was a rain of dry, grey ashes. "f 



It may not be out of place to suggest here that this globular 

 oolitic structure might be looked for in older tuffs in other 

 parts of the world, as for example, in the great Tertiary 

 deposits of the Rocky Mountains, and that its occurrence might 

 serve as a means of indicating the proximity of the vent from 

 which the breccias and tuffs Avere derived, since from the 

 nature of their origin, deposits of this character could not occur 

 at any great distances from the source of supply. 



The third kind of deposit is stream laid volcanic debris in 

 the bottoms of the canyons near where they empty into the 

 sea. This is in all probability largely composed of recent 

 ejecta, but there is considerable old material mixed with it, 

 such as fragments removed from the older tuffs exposed by 

 erosion. These fluviatile deposits are only prominent near the 

 mouths of the larger streams, and are hardly to be separated 

 from the submarine deltas Avhere an enormous quantity of 

 material has been laid down. Unfortunately nothing is known 

 of the changes in depth that have taken place along the coast- 

 line, nor of the effect of coastal landslips that continued to take 

 place for some time after eru^^tions. . These fluviatile deposits, 

 plainly due to the overloading of the streams during the rainy 

 season, are of only relative importance in St. Yincent, and the 

 chances are that after another period of heavy rains only faint 

 traces of them will be left. They are of interest, however, for 

 purposes of comparison with tuffs of other regions, where 

 similar deposits should be found, and where, on account of 

 included fragments of older rocks, the actual age relations with 

 other tuffs of the same series of eruptions might be misinter- 

 preted. They are obviously the youngest deposits in St. 

 Yincent. 



Where fresh sections of the older and younger tuffs have 

 been exposed by landslips from the ends of small spurs and 

 * Op. cit., p. 428. f Op. cit., p. 443. 



