BY A. N. LEWIS, M.C., r,L.B. 



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In the National Park, Lake Nicholls, on the eastern 

 slope of Mt. Field East, and Lake Belcher, under Tyenna 

 Peak, are at approximately the same elevation as Lake Web- 

 ster, and each lies in a cirque. From two to three hundred 

 feet above each, another cirque has been cut, in which now 

 lie Lakes Rayner and Belton respectively. Above Lake Bel- 

 cher, on the opposite side of the valley to Lake Belton, and at 

 the same elevation, there is a ledge which is probably an 

 immature cirque. Above Lake Rayner the side of the moun- 

 tain rises 1,000 feet nearly sheer to the top of the plateau, 

 where the third phase has carved the Field East residual. 



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Above Lake Belton the ridcce rises about the same distance 

 to a small plateau, out of which rise Mt. Field West, Tyenna 

 Peak, and three similar prominences, for a further 200 feet, 

 as residuals from the original pre-glacial mountain plateau. 



I am not yet prepared to say whether these three phases 

 represent three ice invasions, and were separated by inter- 

 glacial epochs of temperate climate, or whether they repre- 

 sent stages in the disappearance of the glaciers cf the last 

 ice invasion. But their occurrence was remarkably uniform 

 throughout Tasmania, and can be traced in all glaciated 

 regions of sufficient elevation. 



The stages in the development of the present Lake Fen- 

 ton were probably as follows: — Prior to the Pleistocene 



