198 DALY. 



If the reef platforms have been finally prepared by wave and 

 current action, it follows that similar benches at appropriate depths 

 should be found in oceanic areas outside of the coral seas. That this 

 is true is speedily evident to any one who examines the large-scale 

 charts. A single example will here suffice. (See also page 240.) 



Continuous with the wide continental shelf now bearing the iVus- 

 tralian Great Barrier Reef, is the coral-free part of the Queensland- 

 New South Wales shelf. The vast lagoon inside the Great Barrier 

 has depths of 2.5 to 75 m. Large areas are comparatively shallow 

 because of a specially rapid rate of organic deposition in Recent time, 

 while the barrier has largely protected them against erosion by ocean 

 currents. The Great Barrier ends at about the 24th parallel of South 

 Latitude, but the shelf continues far beyond, to the southward. On 

 this reefless part the general depths vary from 35 to 110 m. Near the 

 37th parallel, the shelf is 15 to 25 km. in width and is covered with 

 water from 70 to 110 m. in depth. The smaller depths on the reefless 

 part of the shelf are largely exj^lained by local abundance of sand (as 

 north and south of Sandy Cape — Fig. 23), permitting rapid, Recent 

 aggradation. Elsewhere the depths of this part are typical of those 

 foimd on most large continental shelves. As will soon appear, there 

 is no necessity of believing that the entire shelf, now covered with 70 m. 

 of water or less, was formed by Pleistocene wave-benching. But the 

 facts fully suggest that the East Australia shelf is a unit, occupied in 

 the north by vigorously growing coral reefs. (See Figs. 21-24.) This 

 continuity is another principal fact, extremely hard to reconcile with 

 the subsidence theory. 



A related fact is the close similarity' of the depths over isolated 

 banks outside the coral seas to the depths found over the Macclesfield, 

 Tizard, Prince Consort, Padua, Seychelles, or Amirante banks. 

 Though located in the coral seas, these l)anks bear few coral growths 

 or none at all. (See page 190 and Figs. 15, 18-20, and 37.) The 

 depths are there generally very like those in the wider atoll lagoons, 

 though averaging a little more, as expected on the hypothesis of 

 Glacial control. 



It shouhl lie noteii that by no means all of the existing submarine 

 shelves bearing 20 to 40 fathoms (35 to 75 m.) of water, represent areas 

 of benching by Pleistocene waves. Very extensive shelves of this type 

 are found in the Java Sea ; in the sea between Borneo and the Malayan 

 peninsula; to the west of Alaska; and at other localities. The flats 

 mentioned are doubtless best explained as essentially due to long- 

 continued aggradation of the sea floor, while sea-level was at or near 



