46 



ETNA. 



[Ch. XXVI. 



altliougli its original base has been elevated by more in i 

 lavas and ejections. It -l-t-i ■> - n 



must 



small 



of lava streams which are poured forth " 

 century, one only is estimated to issue from the summ'f 



Nor do all 



from 



the lateral eruptions give rise to such hills as would h 

 reckoned amongst the 200 lateral cones before alluded t 

 p. 2, as laid down in Waltershausen's map. Some of the ' 



monticules 



overwhelmed 

 vents. 



How many 



of ashes proceeding from higher 



} formation of all the minor 

 from Etna the whole 



If 



we 



of those now visible, 



together with the lavas and scoriae that have been poured out 



from them, and from the highest crater, during the period 



of their growth, the diminution of the entire mass would be 



extremely slight : Etna might lose, perhaps, several miles in 



diameter at its base, but the aspect of the woody reo-ion 



would not be essentially changed, because other minor cones, 



now concealed, would be recalled as it were into existence by 



the removal of the lava and ejected matter under which they 



now lie buried. As to the height of the mountain during 



the early stages of the phase of lateral eruptions, it may have 



been much greater before its summit was truncated than it 



is now, even if we make allowance for a slight accession of 



height due to the gradual upheaval of the whole mass above 



the level of the sea, as testified by the raised beaches on the 



coast before described. 



To attempt to estimate the number of centuries which have 

 elapsed since the first submarine eruptions began would be 



.^„ ^ , been periods of tranquillity 



may 



idle, because there 



such as that in which the ancient valleys were excavated, 

 enduring perhaps for tens of thousands of years, and then 

 followed by paroxysmal outbursts like that to Avhich the 



No 



may 



Etna since the lateral cones were thrown up. For few, if 

 any, of these heaps of loose scoriee could fail to have been 



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be 



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have 



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 sac 

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 thoi 



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 mari 

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