818 ERUPTION OF THE SOUFRIERE IN ST. VINCENT. 



the west side the i-avine of the Rabaoa Dry River had been about 200 

 feet deep. It is now almost entirely filled up, and the river is slowly 

 cutting its way throug-h the hot sand which occupies it. The same 

 thing- is happening in the Wallibu Valle}', but here erosion is more 

 advanced, and cliffs of gray, hot ash, some 80 feet high, overlook the 

 stream at a point about a mile above its mouth. On the flatter ground 

 between the river gorges which trench these broad valley bottoms the 

 deposit is very much thinner, perhaps 3 to 5 feet on the windward side, 

 but often 12 feet, and sometimes 30 or 1:0 feet on the leeward side. 



The distribution and thickness of the recent ashes is not at all such 

 as would have been expected had these materials merely rained down 

 from above. Wherever there is a hollow it has been filled up, however 

 deep. For some days after the eruption the stream valleys were level 

 with their lianks. On the flat ground the deposit is much thinner, and 

 on the ridges and spurs which stand up prominently there was com- 

 paratively little accunudation. To the mind of a geologist examining 

 these valley s one comparison was irresistibly suggested — they resembled 

 nothing so much as a rugged country covered with ])lown snow. The 

 ash had drifted into and filled up the depressions, while comparatively 

 little had rested on the ridges between. It is conceivable that mud 

 lavas flowed down at an early period in the eruption, and occupied the 

 lower parts of the gorges; but we saw no evidence of this, and as 

 wherever the deeper layers of the ash are exposed they are still burn- 

 ing hot, it is obvious that they could never have reached their present 

 position in the condition of a mud lava. AVhen we saw this country 

 its surface had been deeply scored by the rains, but those who visited 

 it shortly after the first eruption described it as having a smooth, 

 gently rolling surface like that of blown sand. 'This is well shown in 

 photographs taken by Mr. Wilson, of Kingstown, on Ma}' 11. The 

 conclusion was forced upon our minds that innnensc quantities of hot 

 sand had rushed down the hill into these valleys in an avalanche wliich 

 carried with it a terrific blast and piled the ashes deep in the sheltered 

 ravines, at the same time sweeping everything ofl' the exposed ridges 

 which lay between. The rain of volcanic material, which lasted for 

 hours after the hot blast had passed, then covered the surface of the 

 country with a final sheeting of fine dust and scoria. 



When we ascended the Soufriere, the evidence of the passage of a 

 hot blast laden with sand was overwhelmingly clear. The various 

 stages of its action, and its varying intensity at different spots, are 

 most easily observed on the windward side, where the country is more 

 flat and open and there are fewer ravines and spurs to modify the 

 course of its operations than in the Walli])u Valley. 



The track to the summit passes across the llabaca Dry Valley near 

 the shore, then turns upward through the sugar-cane fields of Rabaca 

 and Lot 11. These were covered with 3 or 4: feet of sand and scoria. 



