160 DISTRIBUTION OF CORAL-REEFS. Ch. VI. 
a moderate distance from it where the bottom is 
gently inclined ; hut they never include a deep-water 
moat or lagoon-like channel running parallel to Ik a 
shore. It must, however, be remembered that 
fringing-reefs are frequently breached by deep-water 
channels, wdiere mud has been deposited in front of 
rivers and valleys. 
In all cases, 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 made con- 
spicuous in a map on so small a scale. 
The vermilion spots and streaks represent vol- 
canos now in action, or historically known to have 
been so. They are laid down chiefly from Yon 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 
Bergliaus’ Physical Atlas. Beginning at the eastern side of the 
Pacific, I have added to the number of the volcanos 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 (see my Journal of Researches, 
p. 457). In the Sandwich group there are no active volcanos, 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 Navigator 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 Enter- 
prise, p. 29) that Toofoa and Proby Islands are active volcanos. I 
infer from Hamilton’s Voyage in the Pandora (p. 95), that Proby 
Island is synonymous with Onouafou, but I have not ventured to 
