PHYSIOGRAPHY OF THE AUSTRALIAN ALPS. 377 



many interesting species, have none wliich are exclusively 

 endemic, all having a wide territorial range over the Australian 

 ■continent. 



Among the Cyperaceje, however, there appears to be a few 

 species of the extensive genus Carex, which are restricted to the 

 alpine regions of Victoria and Tasmania, as C. acicularis, i . 

 Bnxbanmii, itc, althougli some of these species are even repre- 

 sented in Europe and Nortli America, and also in North Asia. 

 The impoi'tant order Graminere which, as regards number of 

 species, stands next to the Leguminosje throughout the world, is 

 here represented principally as regai'ds number of species by the 

 genera Dantlionia, Poa, Festuca and others, but in respect to 

 territorial range of single species none are more extensively 

 distributed than the well-known " Kangaroo grass," Anihistiria 

 ciliata. The Poas are the tallest grasses to be met with in these 

 regions. Culms of P. dives are frequently seen to attain a height 

 of twelve feet in shaded hillsides, the whole plant being succulent 

 and nutritious, and may hereafter repay cultivation. All the local 

 Danthonias and Festucas are good fodder grasses. A species of 

 Trisetum, T. siibspicatuni, is apparently restricted to the higher 

 mountain regions of Victoria, New South Wales, and Tasmania. 



GEOLOGICAL STRUCTURE. 



The greater part of the rock-masses which constitute the Aus- 

 tralian Alps, may be described as Palirozoic sediments which have 

 been tilted, folded, compressed, and completely metamorphosed over 

 large areas into crystalline schists. The lower curves of the folded 

 and compressed sediments have been melted ofi' into granite 

 masses. Numerous porphyritic bosses and igneous dykes, now bared 

 by denudation, shew plainly the result of powerful plutonic 

 action, while certain fragmental porphyries and massive felsites 

 remain as a record of intense volcanic activity. The whole complex 

 of sedimentary plutonic and igneous rocks of Palteozoic age are 

 in parts overlain by Tertiary lava flows (sheets of basalt), which 

 form the principal plateau and elevated table-lands, along whose 

 margin some of the present river valleys have been eroded, and 

 the adjoining hills degraded. As previously stated, the Mesozoic 

 rocks — so far as known — are entirely absent in the Australian 

 Alps. 



There are apparently no pre-Silurian rocks in the Australian 

 Alps, but the oldest sediments are referable to the Lower Silurian, 

 and consist of a recurring series of highly inclined, and in most 

 areas slightly metamorphosed slates and sandstones, which are 

 intersected by auriferous quartz veins. In the Mitta Mitta source 

 basin, and in the Upper Tambo basin, these sediments ai'e meta- 

 morphosed into crystalline schists — nodular schist, mica-schist, 

 and gneiss — in some localities the gradual transition from the 



