§ 16. VOLCANO OF KIRAUEA. 831 



has removed the less coherent pre-existing erupted mate- 

 rials.* These buttresses are from two to twenty feet in 

 thickness, and being of immense height, are extremely 

 picturesque ; some of them are composed of trachyte, and 

 others of blue compact basalt with olivine. The surface of 

 the plain is wild and desolate in the extreme, presenting the 

 appearance of a tempestuous sea of liquid lava, suddenly 

 congealed. Innumerable currents of lava are seen piled 

 one upon the other ; some of which terminate abruptly, 

 while others have extended across the Yal, and descended 

 in cascades into the lower fertile regions, where they are 

 spread out in sterile tracts amid the vineyards and orange - 

 groves, f 



The varied and picturesque scenery of Etna, the phe- 

 nomena of volcanic action which are there so strikingly 

 exhibited, as well as those which have taken place in periods 

 long antecedent to human history and tradition, but of 

 which the natural records remain, are described by Mr. 

 Lyell with that vigour and fidelity which characterize all 

 the productions of his pen ; and his works should be con- 

 sulted by those who desire fully to comprehend the nature 

 of some of the most interesting physical changes which are 

 in progress on the surface of our planet.J 



16. Volcano of Klrauea. — Of the existing volcanoes 

 that of Kirauea, in Hawaii. § exhibits volcanic action in its 

 most sublime and imposing aspect. The island of Hawaii, 

 which is about seventy miles long, and covers an area of 

 4,000 square miles, is a complete mass of volcanic matter, 



* See ante, p. 819. 



f See Captain Basil Hall's graphic description of a visit to the Yal 

 del Bove, Patchwork, vol. iii. p. 31. 



$ See Principles of Geology, vol. ii. p. 415. Elements of Geology, 

 vol. ii. 



§ Hawaii is one of the Sandwich Islands, and is well known under 

 its former name of Owhvliee, as the scene of the murder of Captain 

 Cook. 



