^ X\v 



n 



u. 



«ll. 



" ^vliiV, 



leli 



tupti 



I 



I 



on 



lontli ; 



-tin 



Ch. XXYII.l 



GEAIIAM ISLAND IN" 1831 



Gl 



and 3 miles in circumference ; after which it beo-an to di- 

 minish in size bj the action of the waves, and Avas only 2 

 miles round on August 25 ; and on September 3, when it 



Wodel 



i of a 



mile in circumference ; its greatest height being then 107 feet. 

 At this time the crater was about 780 feet in circumference. 

 On September 29, when it was visited bj Mons. C. Prevost, 

 its circumference was reduced to about 700 yards. It was 

 composed entirely of incoherent ejected matter, scoricc, 

 pumice, and lapiUi, forming regular strata, some of which 

 are described as having been parallel to the steep inward 

 slope of the crater, while tlie rest were inclined outwards 



like those of Vesuvius.* "Whe 



determined 



the arrangement of the 



tinually on two steep slopes, that of the external cone and 

 that of the crater, which is always a hollow inverted cone, a 



Fig. 93. 



resemble 



annexed figure (93). But when I visited Vesuvius, in 1828, 

 I saw no beds of scoriae inclined towards the axis of the cone! 

 (See fig. 67, Vol. I. p. 631.) Such may have once existed ; but 

 the explosions or subsidences, or whatever causes produced 

 the great crater of 1822, had possibly destroyed them. 

 ^^Pew of the pieces of stone thrown out from Graham Island 



ifoot in diameter. Some fragments of dolomitic 



limestone 



intermixed 



month 



there 



volcanic substances. During the 



occurred on the S.W. side of the new island a vi~olent ebul- 



htion and agitation of the sea, accompanied by the constant 



column 



from 



Towards the close of October, no vestige of the crater re- 

 clamed, and the island was nearly levelled with the surface 

 the ocean, with the exception, at one point, of a small 



monticule of sand and scorise. 



It was re]3orted that, at the 



* See Memoir by M.C. Prevost, Ann. des Sci. Nat. torn. xxiv. 



