268 RECENT FORMATIONS. 



and Hecla may be taken as familiar instances of volcanic 

 accumulations, and as these have added hundreds of feet to 

 their height, and cast their discharges for miles around dur- 

 ing the current epoch, so have all other active volcanoes 

 "been similarly adding to their altitudes and lateral dimen- 

 sions. One has only to cast his eye over a map of Volcanic 

 Lines and Centres to see what a large area of the globe 

 must have received accumulations of this kind within modern 

 times partly as mountain masses piled up on land, partly 

 as islands upheaved from the sea, and partly as submarine 

 sheets that have flowed as lava, or been cast abroad in 

 showers of dust and ashes. All along the Andes, Central 

 America, Mexico, the West Indies, and the north-western 

 shores of the New World, volcanic accumulations have 

 taken place, and are still taking place, on a grand scale. 

 The same may be said of the Aleutian Islands, Kamtchatka, 

 Japan, the Philippines, and the East Indian Archipelago ; 

 while over the bosom of the Pacific, along the Atlantic 

 islands of Africa, in the Indian Ocean, in the Southern 

 Ocean (as New Zealand), and in the Northern (as Iceland), 

 similar phenomena have marked the course of the Tertiary- 

 period, and must, if we can judge from their present dis- 

 plays, have materially contributed to the exterior crust of 

 our planet. Indeed, as there is no other Recent formation 

 more obvious in its character and mode of accumulation, 

 so there is none more rapid and gigantic in its results 

 a few months being often sufficient to pile up hills of slag 

 and scoriae, or spread abroad sheets of lava hundreds of feet 

 in thickness, and many square miles in extent.* But it is 



* Sir W. Hamilton reckoned the current which reached Catania in 

 1669 to be 14 miles long, and in some parts 6 wide ; Recupero measured 

 the length of another, upon the northern side of Etna, and found it 40 

 miles ; Spallanzani mentions currents 15, 20, and 30 miles ; the stream 

 that flowed from the Skaptar Jokul in Iceland in 1783 was about 50 miles 



