Fig. 1a. — Idealized section of a limestone reef flat, indicating how extreme physico- 

 chemical conditions over the reef flat may facilitate chemical solution of the 

 limestone down to the level of low-water springs, and operate at a maximum 

 (in protected places) at mean sea-level, producing a deep undercut 



Fig. 1b. — Idealized section of the " coastal limestone " cliffs at Point Peron, 

 Western Australia, showing four post-Glacial bench levels cut by the sea at 

 its various stands 



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