406 



INSULAE FLORAS AND FAUNAS WITH 



[Ch. XLI. 



4 



ancient, for lavas proceeding from those vents, and flowin<^ 



helmed 



of ernptions. 



-)f 



made 



from 



Mioce 



T 



•ecent fauna and flora by aid of fossil remains preserved in 



Hartun 



li 



Madeira 



at the height of 1,000 ft. above the sea, a layer of lignite con- 



taining impressions of the leaves of forest trees and some 

 ferns. They appear to belong to some part of the PHocene 

 period, and are certainly of great antiquity, for the nume- 

 rous beds of lava and layers of volcanic ash piled over them 

 are about 1,100 feet thick. Sir C. F. Bunbury, and after 

 him Professor Heer, have shown that these fossil leaves prove 

 Madeira to have been clothed, at the period when they were 

 imbedded (possibly in the mud at the bottom of an old crater) 

 with evergreens and other laurel-like trees, such as Laums 

 and Oreoda2?hne mixed with species of European genera, 

 together with ferns, such as Woodivardia — in fact, with just 

 such forests and such an undergrowth as we now find charac- 

 teristic of the native veoretation of the island. Some of the 



hD 



Heer 



t 



It is a favourite opinion of some naturalists, and one advo- 

 cated by the late Edward Forbes, that the Azores, Madeiras, 

 and Canaries are the last remaining fragments of a contin- 

 uous area of land, which once connected them with the West 



Africa. In order to explain my reasons 

 is hypothesis, I may refer the reader to 



North 



map 



cal Geography of the Sea, and partly on Admiralty charts, for 



Mr 



A 



m 



continental extension involves an amount of change of level 

 so vast, that to assume its occurrence since the close of the 

 Miocene epoch, is quite inconsistent with what we know of the 



1854, vol. X. p. 32(3, and 'Lyell's Ele- 



^ See 'LyeU's Elements,' p. 639. 



t See Buubury, Geol. Quart. Journ. mcnts/ 6th edit. p. 6-12. 



