178 NATURAL SCIENCE [March 



the reef flat ; that it is not so buried suggests that the reef flat as 

 well as the dry land advances seawards. The reef flat is typically 

 seamed with channels ; if these are not excavated by the sea (which 

 is incredible) then they must be enclosed by coral growth. That 

 they are so enclosed is ofiered as proof that the reef flat itself grows 

 seawards, built out probably on a foundation of its own waste. 



Chakles Hedley. 



AtTSTRALIAX MUSEUM, SYDNEY. 



