CORAL-REEFS. 153 



deepish channels, where mud has been deposited. A space 

 of 30 miles in width has been coloured round or in front 

 of the reefs of each class, in order that the colours might be 

 conspicuous on the appended map, which is reduced to so 

 small a scale. 



The vermilion spots and streaks represent volcanoes 

 now in action, or historically known to have been so. They 

 are chiefly laid down from Von Buch's work on the Canary 

 Islands ; and my reasons for making a few alterations are 

 given in the note below. 1 



1 I have also made considerable use of the geological part of 

 Berghaus' Physical Atlas. Beginning at the eastern side of the 

 Pacific, I have added to the number of the volcanoes in the southern 

 part of the Cordillera, and have coloured Juan Fernandez according to 

 observations collected during the voyage of the Beagle {Geol. Trans., 

 vol. v. p. 601). I have added a volcano to Albemarle Island, one of 

 the Galapagos Archipelago (the author's Journal of Researches : , p. 457). 

 In the Sandwich group there are no active volcanoes, except at Hawaii; 

 but the Rev. W. Ellis informs me, there are streams of lava apparently 

 modern on Maui, having a very recent appearance, which can be traced 

 to the craters whence they flowed. The same gentleman informs me, 

 that there is no reason to believe that any active volcano exists in the 

 Society Archipelago ; nor are there any known in the Samoa or Navi- 

 gator group, although some of the streams of lava and craters there 

 appear recent. In the Friendly group, the Rev. J. Williams says 

 {Narrative of Missionary Enterprise, p. 29) that Toofoa and Proby 

 Islands are active volcanoes. I infer from Hamilton's Voyage in the 

 Pandora (p. 95), that Proby Island is synonymous with Onouafou, 

 but I have not ventured to colour it. There can be no doubt respecting 

 Toofoa, and Captain Edwards (Von Buch, p. 386) found the lava of 

 recent eruption at Amargura still smoking. Berghaus marks four active 

 volcanoes actually within the Friendly group ; but I do not know on 

 what authority: I-may mention that Maurelle describes Latte as having 

 a burnt-up appearance: I have marked only Toofoa and Amargura. 

 South of the New Hebrides lies Matthews Rock, which is drawn and 

 described as an active crater in the Voyage of the Astrolabe. Between 

 it, and the volcano on the eastern side of New Zealand, lies Brimstone 



