358 EVIDENCES OF EXTENSIVE GLACIER ACTION AT MT. KOSCIUSKO, 



How this extraordinary feature was formed and placed in such 

 a remarkable jwsition — for it forms, so to say, a ridge in the 

 centre of a valley — is a very perplexing question to answer. 

 After carefully scrutinising its surroundings, however, I have 

 formulated a theory which I think will explain its origin. 



The granite outcrop at its eastern end played no doubt an 

 important part towards its origination. I presume that when the 

 glacier field became reduced to glacier streams, and these so far 

 receded that they only filled the valleys, and the deposition of 

 debris began within their limits, was the time when this strange 

 moraine-dam started to form. The glacier coming over the top 

 of Mt. Twynam down the valley was evidently jammed by the 

 granite outcrop and piled up between this protrusion and the 

 southern branch of the Crummer Range.* Thus blocked, the ice- 

 current must have progressed rather slower at the base than on 

 top when this portion passed over the obstructing granite protru- 

 sion. The upper stratum of the ice, although following on the 

 whole the general direction of the lower one, would naturally 

 expand in a lateral direction, where it was not impeded, and 

 constantly crumbling away and likely dropping down some dis- 

 tance, it must have deposited the ddbris of rock it carried with it 

 in this marvellously evenly shaped configuration. Whilst I see 

 things seemingly clearly enough in my mind's eye, and can picture 

 to myself the locality and its environs, I must admit that it baffles 

 me to offer in words the graphic delineation that is necessary to 

 correctly impart my meaning. I hope, however, that at least to 

 some extent I have been lucid enough to convey an idea of this 

 marvel, t 



* Named by me in honour of my friend Mr. H. S. W. Crummer, the 

 worthy and indefatigable treasurer of Royal Geog. Soc. in Sydney. 



t Two more such singularly formed moraine-dams were observed by me, 

 but none of them can be compared as to the regularity of their shapes to 

 the one near Lake Merewether. One of these is situated at the southern 

 side of the low saddle in the Main Range, not far from the "Dividing 

 Peak," and the other can be found near the lower side of the Etheridge 

 Range (named after Robert Etheridge, jun., Paleontologist), a secondary 

 range that runs almost parallel to the Main Range near Mt. Townsend. 

 Both places are marked on the map. 



