Geography. 79 



nature of the physical geography during the time of 

 the volcanic eruptions already mentioned ? To me it 

 seems to have been somewhat of this sort. 



On the margin of the ancient land, or at some dis- 

 tance therefrom, volcanic eruptions took place in the 

 sea-bottom somewhat of the nature of that which in 

 1831 took place in the Mediterranean between the 

 islands of Pantellaria and the south-west coast of Sicily. 

 This eruption was preceded by an earthquake on June 28, 

 and on July 10 John Corrao from his ship saw a column 

 of water 60 feet high and 800 yards in circumference 

 spout into the air, succeeded by dense steam, which rose 

 to a height of 1,800 feet. On the 18th the same 

 mariner found an island twelve feet high, from the 

 crater of which immense columns of steam and vol- 

 canic ashes were being ejected, ' the sea around being 

 covered with floating cinders and dead fish.' l The 

 eruption continued into August, when, by the ejection 

 of what is often called volcanic ashes, viz., pumice, 

 scoriae, and lapilli, on the 4th of that month the 

 island was said to have been more than 200 feet in 

 height and 3 miles in circumference. From that time 

 it gradually decreased in size, owing to the action of 

 the waves, and towards the close of the year the island 

 had been destroyed and disappeared, leaving only a 

 reef beneath the sea with a black rock in the centre, 

 from 9 to 11 feet under water, and which probably 

 marked the position of the funnel of the short-lived 

 volcano. Before the eruption took place it so happened 

 that Captain (afterwards Admiral) W. H. Smyth 

 sounded on the spot in more than 100 fathoms, and 

 this, added to 200 feet that the island rose above the 

 sea, gives 800 feet as the height of the cone from the 



1 Lyell's Principles of Geology,' vol. ii. p. 60, 12th edition. 



