244 " -^l 'OIINSTON MKMORIAL LKCTl'UK. 



What seems to be specially needed is a systematic map- 

 ping of all the placial evidences, beginning with the oldest, 

 those on the West Ccast. There the jrrcat terminal moraine, 

 so well seen in the railway cuttings in the Lower Eden Val- 

 ley, can be followed north and south, and the outwash-apron 

 gravels together with their peat beds should be carefully 

 differentiated. The retreat of the great ice sheets, belonging 

 perhaps to Riss cr Mindel, or even Giinz time, should be 

 carefully followed up, traces of terminal moraines, Karnes 

 (csars), drumlins, trend of grooves on pavements, carry of 

 erratics, nature, thickness, and time value of varve clays 

 should be noted, together with positions and boundaries of 

 existing or silted up (most of these older Pleistocene glacial 

 lakes have been siltfd up), glacial lake basins, often with a 

 great rock bar (or "riegel") helping to form the lake. Then 

 estimates of the former thickness of the ice sheet may be 

 formed from a close .study of the height up to which old 

 glacial markings can be traced on "tinds," "horns," or "nuna- 

 takr." Afterwards evidences of the later glaciations super- 

 imposed on the older can be studied and mapped, culminating 

 in the final small mountain glaciers. 



Truly, a fascinating and awe-iiispiring quest! Any 

 one familiar with the phenomena of existing Polar ice sheets 

 and Alpine glaciers can visualise the tiers of Tasmania under 

 their snowy mantle with great glittering ice-fields between ; 

 can see the glorious sapphire blue of the deep crevasses where 

 the ice sheet plunged down the steep mountain escarpments 

 of the West Coast, and mark the long sinuous lines of 

 moraine streeling away from nearby nunatakr to be lost to 

 sight in the far distance; can hear the harsh roar of the 

 sub-glacial stream rolling its tawny waters past the great 

 terminal moraine, and spreading, far beyond, its alluvial fan 

 of gravel and sand; can follow every phase in the retreat of 

 the ic3 invader; the ponding back of the glacial streams to 

 f;rm lakes in rear of the terminal moraines, the silting up 

 of the older lakes and their passing into peat swamps and 

 button grass flats. And then, too, he can see all the won- 

 derful phenomena of the rc-advance of the ice, as told so well 

 for Switzerland by Nussbaum, and finally view the highlands 

 alone snow-covered, the white of the come glaciers, framed 

 in dark rock, whilt all the rest of the 'slo is under a living 

 garment of green. 



What changes the Tasmanian man must have witnessed. 

 Probably some of these glacial phases with the gradual 

 drowning of the Bass land bridge, which so effectually check- 



