128 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



The coral reefs found north of Queensland, in Torres Strait, and 

 on both sides of it extending well out toward the 100 fathom line on 

 the east and west, were probably formed much in the same way in which 

 I imagine them to have progressed from the old shore line inland as 

 fast as the land was reduced to the level of the sea. 



Darwin and Dana have both assumed, in their discussion of the theory 

 of coral reefs, that the subsidence which they claimed as necessary for 

 the formation of barrier reefs and of atolls took place during the present 

 epoch. 1 It seems to me as if the geological history of Australia throws 

 considerable light on this subject, and that the great subsidence during 

 which the Australian desert sandstone was laid down was perhaps con- 

 nected with the disappearance of the Pacific continent or archipelago, of 

 which the Australasian Islands are now only the remaining summits ; arid 

 that denudation of the remnants of this Pacific Island area has been going 

 on apace with that of the Australian coast (Queensland), cutting down 

 the peaks to form huge banks and isolated islets and islands with more or 

 less extensive banks, upon which and on the flanks of which corals have 

 during the present period found their resting place, and have grown to 

 form barrier or fringing reefs and atolls from a comparatively shallow 

 base line, subsidence having played in their formation but an insignifi- 

 cant part. 



The unfathomable depth of which we hear so much in all discus- 

 sions regarding coral reef formations is neither greater nor less than 

 the depths found along any oceanic shore of the same district where 



" At the close of the carboniferous period there was a general depression of the 

 whole land to such an extent that all but the higher summits of the more promi- 

 nent ranges were submerged by the ocean, and only the limits of the future conti- 

 nent indicated by a series of rocky islands extending from Tasmania nearly to Cape 

 York, — the higher lands of southern and western Australia alone escaping. . . . 

 The sedimentary strata of the cretaceous are found abutting on the older rocks, 

 but over the rest of Australia these deposits cover the summits of even the higher 

 ranges. . . . This condition of submergence must have continued until the commence- 

 ment of the tertiarj 7 period. . . . Following this there was a general ri~t- above the 

 ocean, and Australia must have appeared as a continent with nearly its present 

 outline, though the interior probably long retained the condition of a shallow in- 

 land sea, communicating with the ocean through Spencer Gulf. The climate was 

 then much moister. Denudation of extensive areas then commenced, leaving 

 only escarpments and' table lands to mark the original level of the surface. Only 

 gradually the climate became drier, the lakes were changed to dry plains, and the 

 present condition of things gradually came into existence." 



x Yet Dana in his "Corals and Coral Reefs" (p. 403), in one instance speaks of 

 the continuity of the coral reefs from earlier periods, if not from the tertiary to the 

 present day. 



