114 Charles Fenner : 



The lakes may he rouglily classified as (i.) solution lakes, (ii ) 

 cut-offs, (iii.) basalt dainuied, and (iv.) those (in basalt sheet. 



(i) Solution Lakes. — This type, dealt with bv Professor Gregory, 2 

 is common. Mitchell had close experience with a large numijer, and 

 deals with them in some detail. I'ndoubtedly wind erosion plays 

 a large part in forming many of these lakes, as shown by the 

 frequently occurring crescentic bank of sand on the eastern shores. 

 A beautiful drawing of the group called the Greenhill lakes is 

 given by Mitchell in Vol. II. of his journal, plate XXXII. 



(ii) Cut-offs. As before mentioned, these occur in the wider and 

 more mature portions of the Wannon and Glenelg, especially where 

 Jurassic mudstones are dominant. 



(iii.) Swamps and lakes caused by the damming up of streams 

 by lava flows are common northward from Glenthompson towards 

 Mount William. These include the Cockajemmy lakes. Larger ones 

 occur west of Mount Abrupt. 



(iv.) The lakes found on the basalt sheet itself are numerous and 

 shallow. Tliey are similar to those found all over south-western 

 Victoria, and bear witness to the innuaturity of the drainage 

 systems. They are usually ascribed to one or more of the follow- 

 ing agencies :— Sagging of the basalt, the meeting of tw-o or more 

 lava flows, wind erosion, and more rarely, crater depressions. 



VII.— The Hummocks. 



This remarkable natural feature deserves a special section for 

 itself. It consists of a hill, a little over 450 feet high, cut through 

 bv two steep-sided gorges — those of the Wando and the Wando Vale 

 ponds. An observer coming eastwards up the wide, open valley 

 of the Wando, cannot fail to be struck by the fact that tliis hill 

 lies riglit across the valley almost at right angles to the course of 

 the stream. Closer observation is necessary to show that it is cut 

 through by the tw^o streams named, which narrow their valleys down 

 to gorges a cliain or less in width. A detailed survey of the imme- 

 diate area was made under the direction of Mr. 0. A. L. Whitelaw, 

 Field Geologist, Geological Survey of Victoria, and is shown in 

 Figure 5. 



To the traveller along the Harrow road to the east, a similar 

 puzzle is presented of two wide U-shaped valleys suddenly nar- 

 rowed to two small V-shaped guts. Since it lies on Major Mitchell's 



Geograplij' of Vittoria, pp. 132 et serj. 



