Geograph}! of North- Wederii Tasmania. 181 



tion and earth movements.^ Nor is tliei-e any evidence, as far as 

 I am aware, that Tasmania has been uplifted, in Cainozoic times, 

 much above its pi'esent leveh'- It is indeed possible, as main- 

 tained by Montgomery, that the glacial deposits of Tasmania 

 were formed when the counti-y stood some hundreds of feet 

 below its present level. The western glaciers followed the 

 existing valleys, occupying those between Mount Sedgwick and 

 Mount Tyndall, between Mount Sedgwick and Mount Lyell, and 

 down the King River to the east of Mounts Lyell and Owen. 

 The course of these valleys had been determined by earth move- 

 ments in pre-glacial times ; and the general evidence renders it 

 highly improbable that they were scooped out by glacial action, 

 although the glaciers may have deepened and modified them. 

 Hence the diversion of the King River from its old course 

 through the Sedgwick Valley, to its present circuitous route to 

 the south of Mount Jukes, was probably caused during the 

 latter part of the glacial period. The damming up of the 

 Sedgwick Valley by ice and moraines was quite sufficient to cause 

 the drainage from the glaciers in the Upper King Valley to 

 overflow at the lowest gap on the southern margin of the King 

 basin ; and the lowest available outlet was between Mount 

 Huxley and Mount Jukes. 



The glacial deposits around Mount Lyell are more recent than 

 the formation of the Henty pene-plain, for that plain was made 

 by a pre-glacial river, and some glacial deposits occur in valleys 

 cut through it, as at Queenstown ; but the difference in time was 

 probably small. The pene-plain was certainly formed when 

 western Tasmania stood a few hundred feet lower than it does 

 now ; and Montgomery may be correct in his view that the 

 glaciation of Tasmania occurred in this period of depression.'' 

 Mr. R. M. Johnston does not favour the idea of any considerable 

 earth movements in Tasmania in recent geological times. He 

 says,^ " In Tasmania there is little evidence of physical disturb- 



1 See for example, "Contributions to the Glacial Geology of Spitzbergen," Quart. 

 Journ. Geol. Soc, vol. liv., ISiW, p. 224. 



2 The flrowiicd valleys of the Tainar and the Derwciit do not necessarily indicate a 

 subsidence of the whole of Tasmania. 



3 Montgomery, A.: " Glacial Action in Tasmania." I'roc. Uoy. Soc. Tas, 1893(1894), 

 p. 165. 



4 Johnston, K. 11.: "Geology of Tasmania," p. 326. 



