“Coral Formations”

Abstract

I LATELY discussed Murray's theory of coral formation with a class of boys and girls (fourteen to sixteen years of age), and they raised two questions which I am unable to answer, (1) If sea water dissolves the coral near the surface at such a rate as to form a lagoon, why does it not dissolve the limestone foundation even more rapidly? (2) After a reef has progressed a considerable distance from the shore, and a channel of open water is formed between, why should not the reef extend back again shorewards? How could such a channel as exists between Australia and its Great Barrier Reef ever have been kept open? These seem to be valid and serious objections: will some expert be kind enough to answer them?