RANGE IN DEPTH OF CORALS. 117 



Outside of the reef of Upolu, corals were seen by the writer 

 growing in twelve fathoms. Lieutenant Emmons brought up 

 with a boat-anchor a large Dendrophyllia from a depth of 

 fourteen and a half fathoms at the Feejees ; and this species 

 was afterward found near the surface. But Dendrophyllia, it 

 may be remembered, is one of the deep-water genera. 



These facts, it may be said, are only negative, as the sound- 

 ing-lead, especially in the manner it is thrown in surveys, would 

 fail of giving decisive results. The character of a growing 

 coral bed is so strongly marked in its uneven surface, its deep 

 holes and many entangling stems, to the vexation of the sur- 

 veyor, that in general the danger of mistake is small. But al- 

 lowing uncertainty as great as supposed, there can be little 

 doubt after so numerous observations over so extended regions 

 of reefs. 



The depth of the water in harbors and about shores where 

 there is no coral, confirms the view here presented. At Upo- 

 lu, the depth of the harbors varies generally from twelve to 

 twenty fathoms. On the south side of this island, off Falealili, 

 one hundred yards from the rocky shores, Lieutenant Perry 

 found bare rocks in eighteen and nineteen fathoms, with no ev- 

 idence of coral. There is no cause here which will explain the 

 absence of coral, except the depth of water; for corals and 

 coral reefs abound on most other parts of Upolu. Below Fa- 

 lelatai, of the same island, an equal depth was found, with no 

 coral. Off the east cape of Falifa harbor, on the north side of 

 Upolu, Lieutenant Emmons found no coral, although the depth 

 was but eighteen fathoms. About the outer capes of Funga- 

 sa harbor, Tutuila, there was no coral, with a depth of fifteen 

 to twenty fathoms ; and a line of soundings across from cape 

 to cape, afforded a bottom of sand and shells, in fifteen to 

 twenty-one and a half fathoms. About the capes of Oafonu 



