Diagram to represent an imaginary section of the Great Barrier reef. 

 The proportions ore enormously distorted, tlie perpendicular scale being 

 fifteen or twenty times greater than the horizontal one. 



a Sc« outside the barrier, generally unfathomable, 

 b. The ncniul biurier. 



tr. Clear channel inside the harrier, generally uboul 1,1 or 20 fathoms dMfv 

 d. The Inner reefs. 



«. Shoal channel between tlie inner n-rf* and the shore, 



F. The gn-fii butlreisjif calcareous ruck, fumu <! .if rorut und the detritus of coral* and 

 shells. 



ft. The main land, formed of granites and other similar rocks. 



