666 GEOLOGICAL NOTES ON KOSCIUSKO, 



or less free of snow, while the snow is banked deep on all the 

 south-east slopes, 



As regards the thickness of the ice-sheet during the maximum 

 glaciation, there is conclusive evidence now that it was able to 

 cross the Snowy Valley and over-ride Charlotte's Pass Valley, the 

 whole of Spencer's Creek Valley, and plunged over the south- 

 eastern edge of the Plateau into the Thredbo Valley. In order 

 to do this, the ice in the Snowy Valley must have had a thick- 

 ness of not less than 1000 feet. Thus, in view of this recent 

 evidence, one is able to state that the Kosciusko ice-cap at the 

 time of the maximum glaciation was fully twelve times as large 

 as was formerly stated, and that the ice was at least double the 

 thickness of the amount originally calculated. 



If now a summary be given of the probable events which pre- 

 ceded, accompanied, and followed the Pleistocene Ice Age at 

 Kosciusko, it may be provisionally grouped as follows : — 



A late Tertiary peneplain, formed of granite, gneissic rocks, 

 and schists, was uplifted to a general level of about 3000 feet 

 above the sea. From Cooma towards Kosciusko a further upward 

 warping took place which led to the peneplain acquiring an 

 inclination towards the north and east; this gave the Snowy 

 River its original northerly to N.N.E. trend near its source. As 

 the warping progressed, and the earth's crust towards the S.E. of 

 the Kosciusko Plateau was put in tension, shearing followed, 

 resulting in the great fault along the Thredbo Valley. Cross- 

 faults also developed at Pretty Point and along Digger's Creek, 

 marked now by a strong feature as well as freshwater springs, 

 and probably also at Sawpit Creek. Possibly another fault may 

 have formed on the south-east side of the Snowy Valley, pro- 

 ducing a long narrow trough; possibly a lake may have been 

 produced at the bottom of this trough, and the remarkable gravel 

 banks to be seen two miles to the south-east of the Accommoda- 

 tion House on the Thredbo may be of lacustrine origin and ante- 

 date the coming down of the rocky bar near the mill-race below 

 Jindabyne. The fault with its easterly throw at Barney's Ridge, 

 which may have given origin to Lake Coolamatong, may have 

 formed about the same time. 



