Dredging on the continental shelf of New South Wales between Crowdy Head and Bateman's Bay has shown that three belts of sediment can be distinguished: (1) the near‐shore coarse sediments, (2) a belt of fine terrigenous sediments and (3) an outer belt of coarse calcareous sediment which covers most of a wide flat plain (over 12 miles wide in the north) existing from 70 fathoms out to the continental shelf break at 85 to 100 fathoms. This calcareous material is derived from shells, mostly molluscan, living at the present time at these depths. Suggestions are offered on the causes of the topography and distribution of the sediments.