RANGE IN DEPTH OF CORALS. 1 1 ."> 



Ehrenberg, by his observations on the reefs of the Red Sea, 

 confirmed the observations of Quoy and Gaymard ; he conclud- 

 ed that living corals do not occur beyond six fathoms. Mr. 

 Stutchbury, after a visit to some of the Paumotus and Tahiti, 

 remarks, in Volume I. of the West of England Journal, that 

 the living clumps do not rise from a greater depth than 16 or 

 17 fathoms. 



Mr. Darwin, who traversed the Pacific with Captain Fitz- 

 roy, P. N., gives 20 fathoms as not too great a range. 



In his soundings off the fringing reefs of Mauritius, in 

 the Indian ocean, on the leeward side of the island, he ob- 

 served especially two large species of Madrepores, and two 

 of Astraea ; and a Millepora down to fifteen fathoms, with 

 also, in the deeper parts, Seriatopora ; between fifteen and 

 twenty fathoms a bottom mostly of sand, but partly covered 

 with the Seriatopora, with a fragment of one of the Madre- 

 pores at twenty fathoms. He states that Capt. Moresby, in 

 his survey of the Maldives and Chagos group, found, at seven 

 or eight fathoms, great masses of living coral ; at ten fathoms, 

 the same in groups with patches of white sand between ; and, 

 at a little greater depth, a smooth steep slope without any 

 living coral ; and further, on the Padua Bank, the northern 

 part of the Laccadive group, which bad a depth of twenty-five 

 to thirty-five fathoms, he saw only dead coral, while on other 

 banks in the same group ten or twelve fathoms under water, 

 there was growing coral. 



In the Ped Sea, however, according to Capt. Moresby and 

 Lieut. Wellstead, there are, to the north, large beds of living 

 corals at a depth of twenty-five fathoms, and the anchors were 

 often entangled by them ; and he attributes this depth, so 

 much greater than reported by Ehrenberg, to the peculiar pu- 

 rity, or freedom from sediment, of the waters at that place. Kot- 



