322 E, Howe — Tuffs of the Soufriere, St. Vincent. 



as clean as the ridges. It was only in the lower valleys, whose 

 directions were more or less transverse to that of the blast, that 

 great accumulations of ejecta were formed. Following this 

 blast came a fall of lapilli and dust from clouds that had been 

 carried upward, and not until then were the ridges and upper 

 ravines covered with new material to an appreciable extent. 



In all probability these events did not take place in as simple 

 a manner as has been indicated, but were complicated by 

 repeated eruptions of greater or less intensity, but which would 

 hardly modify the general relations of the two deposits. What 

 did undoubtedly affect the character of the deposits filling the 

 valleys were torrents, due to the unusual precipitation of rain 

 connected with the eruptions. The action of these streams was 

 very interesting and peculiar and was described in detail by 

 the first observers. The loose and unconsolidated materials 

 were picked up so readily by the torrents that the streams 

 became overloaded and clogged, and dams were formed which 

 soon gave way,- permitting a rush of accumulated and partly 

 cleared water to lower portions of the channel, where the 

 process was repeated. Hovey,* in speaking of the Wallibou 

 River, describes how '^ it cut into and undermined the beds of 

 dust and lapilli along the banks. Its waters became so over- 

 loaded with sediment that they could only flow in pulsations, 

 showing that intervals of time were needed by the stream to 

 gather strength to force its way along with its burden." 

 Water was also soaking into the beds of extremely hot ejecta 

 and being converted into steam, which broke forth at intervals 

 with force enough to throw dams across the streams and to divert 

 them from their channels. These processes undoubtedly did 

 much to add to the incoherent character of the valley fillings 

 and to obliterate in many instances their original stratification. 



Of the submarine deposits nothing is known. Extensive 

 deltas were developed at the mouths of the larger streams, 

 only to disappear after a brief existence, the angle of the 'sub- 

 marine slopes being too great to support the unwonted loads 

 which had been suddenly laid down upon them. 



One cannot fail to be impressed by the geological processes 

 that are being carried on at the Soufriere — the ejection and 

 deposition of comminuted rock, the first partial consolidation 

 into stratified tuffs, their erosion, and i-edeposition on the sea- 

 bottom. For years to come the West Indian volcanoes should 

 continue to be worthy of the detailed study of the general 

 geologist, as well as the petrographer and physicist. 



U. S. Geological Survey, Washington, D. C. 

 *0p. cit., p. 344. 



