CORAL REEFS, AND ISLANDS. 265 



affirmed that, in the more northern parts of the Red 

 Sea, there are extensive beds of living coral at a- 

 depth of 150 feet. Within the lagoons of some of 

 the Marshall atolls, where the water can be but 

 little agitated, there are, according to Kotzebue, 

 living beds of coral in 150 feet. Captain Beechey 

 states that branches of pink and yellow coral were 

 frequently brought up from between 120 feet and 

 150 feet off the Low atolls, and Lieutenant Stokes, 

 writing from the north-west^coast of Australia, says that 

 a strongly-branched coral was procured there from 

 80 feet. Professor Agassiz observes that, about the 

 Florida reefs, the reef-building corals do not extend 

 below 60 feet. Professor Dana remarks that in the 

 Wilkes's Exploring Expedition the soundings, in 

 the course of the various and extensive surveys, 

 afforded no evidence of growing coral beyond 120 feet. 

 Among the Fiji Islands the extent of coral reef 

 grounds surveyed was many hundreds of square 

 miles. The reefs of the Navigator's Islands were 

 also sounded out, with others of the Society group, 

 and, through all these regions, no evidence was 

 obtained of corals living at a greater depth than 

 90 feet to 1 20 feet. He concludes that, " there is 

 hence little room to doubt that twenty fathoms 

 (or 1 20 feet) may be received as the ordinary 

 limit in depth of reef corals in the tropics." 



Not less interesting, or important, is the question 



