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e 





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in. 



ex. 



8 fill 



led 



1 1 %1 

 at. 



ie % to 

 - are 



o 



and 



a 



Jr geon 



central 



:li 



e 



ca 



sence of 



Honto 



appears 

 ivourite 



re some 



ris own 

 ire cer- 



. and on 



f 



to have 

 1. 'Tie 

 position, 



ents on 



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 mis, W 



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that the 

 On 



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>.'t 



Ob. xxiv.] 



EEUPTION OF MONTE NUOVO. 



615 



j.j ie supposition, then, that pre-existing beds of pumiceous 



Nuovo 



s 



acknowledged that the perfectly undisturbed state of the con- 

 tiguous soil on which these ancient monuments stand, is very 

 different from what might have been expected. 

 Mr. Darwin, in his ' Volcanic Islands,' has described several 

 •ateriform hills in the Galapagos Archipelago as composed 

 of tuff which has evidently flowed like mud, and yet on con- 

 solidating has preserved an inclination of twenty and even 



ci 



o Si 



lieets 



thirty degrees. The tuff does not fold in continuou 

 round the hills as would have happened if they had been 

 formed by the upheaval of horizontal layers. The author 

 describes the composition of the tuff as very similar to that 

 of Monte JSTuovo, and the high angles at which the beds 

 slope, both those which have flowed and those which have 

 fallen in the form of ashes, entirely removes the difficulty 

 supposed by M. Dufrenoy to exist in regard to the slope of 

 Monte ISTuovo, where it exceeds an angle of 18° to 20°. * Mr. 



Dana, also 



account 



s 



hows 



that in the ' cinder cones 3 of that region, the strata have an 

 original inclination of between 35° and 40°, while in the 

 4 tufa cones ■ formed near the sea, the beds slope at about an 



angle of 80°. 



The 



Ul 



observed in the 



Samoan or Navigator Islands in Polynesia, that fragments of 

 fresh coral had been thrown up together with volcanic mat- 

 ter to the height of 200 feet above the level of the sea in 

 cones of tufa. ± 



-r 



In October, 1857, 1 re-examined Monte ISTuovo in company 

 with Prof. A. Scacchi. On the south side of the mountain 



I saw both large and small blocks of trachyte entering into its 



composition, together with scorise, just as we might have ex- 

 pected from the accounts handed down to us of the eruption. 

 In the interior of the crater on the east and north-east side 

 an internal talus is seen, the beds of which slope at angles of 

 26° and 30° degrees towards the centre or axis of the cone as 

 at a ? fig. 65. Such taluses are well known as characterising 





* 



aote. 



Darwin's Volcanic Islands, 106, Expedition, in 1838—1342, p. 354 



f Geology of the American Exploring 



J Ibid. p. 328. 



