PROCEEDINGS OF SECTION C. 413 



at Magnetic Island was recorded by W. S. Kent (Proc. Roy. Soc, 

 Qland. vii., 1891, p. 39) ; but Haddon, SoUas, and Cole consider that 

 no elevation has occurred in Torres Strait (Trans. Roy. Irish Acad., 

 XXX., 1894, pp. 460, 472). 



Whatever the history of the Great Barrier was, the reefs of the 

 Coral Sea, such as the Lihou Reefs, Flinders Reefs, and the Herald 

 Cays, shared in it. 



VII. SUMaiARY. 



The growth of an individual reef is shown to proceed in a regular 

 cycle. If the reef reaches the surface with its axis along the wind, then 

 its shape endures ; but if across the wind, then its extremities are 

 produced backward, forming first a crescent, later a horseshoe, and 

 lastly an oval, thus enclosing a lagoon. Descent at this stage arrests 

 development or rejuvenates the reef. In quiesence ■^he lagoon walls 

 broaden, the lagoon is obliterated with sediment, a vegitated sand- 

 bank spreads on the summit, and the atoll, grown to a cay, has arrived 

 at maturity. 



It is argued that the negroheads are not, as has been advanced, 

 relics of former raised reefs, but are tossed up by hurricanes. 



Not every writer on the Barrier Reef region has expressed an opinion 

 on the question of formation during subsidence. On the Darwinian 

 side are ranged Jukes, Kent, and Andrews, and opposed to it is Agassiz. 

 The present observers find a verdict for the Darwinian view on these 

 grounds: — That the mainland of Queensland shows subsidence in (1) 

 drowned river mouths, (2) the formation of its bays and islands, and 

 (3) the sinking of an isthmus that once continued the Cape York Penin- 

 sula to Papua. That the sinking of the Queensland coast is part of a 

 general movement which affected the whole of Eastern Australia and 

 Tasmania ; probably correlated with an upward movement in the 

 Australian interior between the 135th and 140th meridians, and per- 

 haps on the north shore of the Papuan Gulf ; the Barrier trough 

 thus ending in the valley of the Fly River. That the Barrier does 

 present (which has been denied) a steep outward face agreeable to the 

 Darwinian hypothesis. That ejections from the Murray volcano 

 show coral formation to occur there at considerable depths ; and that 

 the maturity (a term here introduced into coral geology) of the northern 

 reefs indicates slow subsidence followed by quiesence. 



DESCRIPTION OF PLATES. 



Plate I. Sections across three typical coral reefs showing the 

 physiography of the same. 



Plate II. Map of the reefs near Cooktown, from the Admiralty 

 chart, showing direction of traverses and contour of sea-floor and reefs. 



Plate III. Sketch map to show position of reefs studied and relation 

 of areas of elevation to those of depression. 



