350 EVIDENCES OF EXTENSIVE GLACIER ACTION AT MT. KOSCIUSKO, 



maintained to have discovered near the base of this mountain and 

 some distance further east.* 



During my first visit to the Snowy Mountains (Feb., 1889) I 

 carefully looked for strise and polished surfaces on the rocks 

 described by Dr. v. Lendenfeld, particularly in Wilkinson Valley, 

 but could not agree with him that they retained such traces, 

 although the general appearance when looked at from a distance 

 favoured the theory that glaciers had ground them down, and 

 that some of the valleys had undergone a prolonged glacial action. 

 On none of the many solitary rocks and exposed rock-surfaces 

 (except in one instance that will be referred to below) I examined 

 then and since have I found j^olished surfaces, nor the charac- 

 teristic striae seen on most of the reliable roches moutonnees. If, 

 however, the nature of the rock formation is taken into considera- 

 tion, the absence of these features can scarcely be surprising, because 

 its tendency to weather is so great that it forbids one to expect 

 the retention of polish or striation for any length of time. I am 

 of the opinion that, except where buried in moraine deposits, very 

 few polished and striated rock fragments will be discovered in this 

 district. The principal rock of the whole system of the Australian 

 Alps is a gneisic granite, often rather coarsely crystallised and 

 occasionally friable when exposed. This rock changes in many 

 places into true gneiss, splendid illustrations of which are afforded 

 in the beds of nearly all the tributaries of the Snowy River on 

 the high elevations. These rocks occur everywhere on the highest 

 portion of the Snowy Mountains except in one part (between 

 Dividing Peak and Mt, Twynam), where slate overlies the granite 

 and forms several secondary ranges. Neither of these rocks, it 

 will be admitted, is very weather-resisting, nor can they with- 

 stand the erosive action of the atmosphere and the severe changes 

 of temperature for a great length of time. In fact, in my opinion, 

 a couple of centuries would almost suffice to completely obliterate 

 all the unmistakable evidences, such as polish and strias. 



* L.c. p. 10. Dr. R. von Lendenfeld says — "I have found no moraines 

 in the district which might indicate that once glaciers existed there, but I 

 have found rocks polished by glacial action in many places." 



