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 disoussion 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." 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 ; and 
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 eretaceous 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 tertiary period. ... Following this there was a general rise 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.” 
1 Yet Dana in his “Corals and Coral Reefs” (p. 403), in one instance speaks of 
the gontinuity of the coral reefs from earlier periods, if not from the tertiary to the 
present day. 
