300 H. S. Summers: 



River system consequent on the extension of the length of the 



river owing to the formation of the coastal plains of South 



Australia. This being so, it follows that this area was formerly 



part of an extensive peneplain, the somewlial. i'rr£.rv,,i-.. — ^ 



of f 



rod 



up • 



wou 



grav 



indie V.X 



the jLc^inmaraon would be due to deposition of fine silt during 

 flood times, so that the ge'neral structure of the alluvial deposits 

 would consist of irregularly bedded clayey material, with 

 " horses " of coarser material formed along former main stream 

 courses. 



In any channelling which might be required for irrigation 

 purposes it would be necessary to guard against loss through 

 soakage into the sand and gravel beds. If the structure be as 

 indicated, it follows that there would be an unequal distribution 

 of the underground water, as the supply at any place would 

 depend on the surface contour of the old pene-plane, and on 

 the distribution of the sand and gi-avel beds throughout the 

 finer-grained clayey material. This means that it will not 

 follow that a plentiful supply of water will be found in any part 

 of this area because a good well exists on a neighbouring farm. 



It is therefore certain that wells cannot be depended on to 

 give an adequate supply of water over the whole area, and this 

 country must depend on large dams or on a supply derived from 

 some large reservoir. 



Summary. 



1. The general physiography of the area is described, and it 

 is pointed out that Broken Creek represents the former main 

 course of the Broken River, the present bed of the river from 

 the junction to Shepparton being of comparatively recent origin. 



2. The geological sequence of the rocks in the proposed 

 water conservation area is set out, particular attention being 

 directed to beds of conglomerate, the origin of which is to a 

 certain extent in doubt. 



