§ 19. SUBMARINE VOLCANOES. 839 



a small island gradually appeared, having a crater on its sum- 

 mit, which ejected scoria?, ashes, and volumes of vapour ; the 

 sea around was covered with floating cinders and shoals of 

 dead fishes. The crater attained an elevation of nearly 200 

 feet, with a circumference of about three miles, having a cir- 

 cular basin full of boiling water of a dingy red colour. It 

 continued in activity for three weeks, and then gradually 

 disappeared. In 1833, two years after its destruction, a 



Lign. 188.— Volcanic Island thrown up in the Mediterranean in 1831. 



dangerous reef remained, eleven feet under the water ; in the 

 centre of which was a black volcanic rock (probably the 

 remains of the solid lava ejected during the eruption), sur- 

 rounded by shoals of scoriae and sand. Its appearance, 

 when visited by M. Constant Prevost, is shown in this 

 sketch {Lign. 188), from a drawing with which he favoured 

 me. From these facts it is certain that a hill, 800 feet high, 

 was here formed by a submarine volcanic vent in the course 

 of a few weeks. The occurrence of shoals of dead fish will 

 not fail to remind you of the ichthyolites of Monte Bolca 

 (ante, p. 265) : and there can be no doubt that vast numbers 



