THE AUSTRALIAN ALPS. 



359 



which lie west of the farthest sources of the Murray, a frontal moraine dams up a 

 little fluvial valley at an elevation of 2,950 feet. 



In the Australian Alps the prevailing formations are of great age, consisting 

 of granites and Silurian masses interspersed with porphyries, diorites, and basalts. 

 Here and there tertiary rocks overlie the valleys, but are always disposed horizon- 

 tally, whereas the surrounding strata have been diversely folded and dislocated. 



Fig. 155. — Australian Alps. 

 Scale 1 : 3,250,000. 



Depths. 



to 100 

 Fathoms. 



100 Fathoms 

 and upwards. 



60 Miles. 



Notwithstanding the intervening depressions the same general features reappear 

 farther west in the Victoria highlands, and even in Tasmania, which belongs in 

 great measure to the same geological epoch. The Pyrenees, which run parallel 

 with the coast north-west of Melbourne, and the Grampians, whose irregular forms 

 stretch farther west, are also of Silurian formation, though less elevated than the 

 Alps, Mount William, the culminating point in the Grampians, being scarcely 

 5,600 feet high. 



But nowhere in Australia have igneous formations been more developed than 



