RANGE IN DEPTH OF CORALS. 1s 
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 as to the general fact 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 capc 
to cape, afforded a bottom of sand and shells, in fifteen to 
twenty-one and a half fathoms. About the capes of Oafonu 
