AUSTRALIAN QUATERNARY CLIMATES AND MIGRATION 



67 



is mainly mud and sand but one sounding bottomed at a depth of 

 396 feet below existing sea-level, or 132 feet below the mean level 

 of the glacial coastal plain, on "dead coral." The living range 

 of coral is 120 feet, so that, taking this extreme range, sea-level 

 when the coral was alive was 276 feet lower than it is now, an 

 estimate, excluding adjustments for tectonic movement, that 



FIG. 12. 

 Mid-Postglacial Coastal Plain. 



agrees fairly well with Daly's figure of 294 feet: if the coral lived 

 on the bottom at a depth of 102 feet, there is complete agreement. 

 During the last glacial period, the Flinders, the trunk-stream of 

 the mature eastern river-system of which the Roper, Nicholson, 

 Leichhardt, Norman, Mitchell and other streams were part, 

 crossed the coastal plain and emptied into the lowered sea-level of 

 the Arafura Bight (Figs. 10 and 12). This system is a Pleistocene 

 one and the trunk-stream had to adjust itself to the lowered sea- 



