286 TOILERS IN THE SEA. 



one of the naturalists of the Challenger expedition, 

 as will be apparent from the subjoined extract, which 

 sets forth briefly the views entertained by him on the 

 subject, and at first communicated to the Royal 

 Society of Edinburgh, in 1880. 



" According to Mr. Murray, the observations of the 

 reefs at Tahiti support the view that the reefs have 

 been built from the shore seawards, and that the 

 lagoons have been, and are still being, formed by the 

 removal of the inner, and dead portions of the coral 

 reef, by the solvent action of sea water. The islands 

 in the harbour, and lagoons, are regarded as portions 

 of the reef which have been left standing, but will 

 ultimately be removed, and, in confirmation of this, it 

 is pointed out, that on the inner part of the reef there 

 are large and massive specimens of the coral which 

 are now dead, but which probably flourished at the 

 time when the outer edge of the reef was at the 

 position in which they are now found. The steep 

 slope which is found on the outer edge of the reef, 

 between the depths of 35 and 200 fathoms, is 

 believed to be formed by huge masses and heads of 

 coral, which have been torn away from the ledge, 

 between the edge of the reef and 35 fathoms, during 

 storms, or by overhanging masses which have fallen 

 by their own weight. In this way a talus has been 

 formed on which the corals, living down to 35 fathoms, 

 have found a foundation on which to build further 



