300 H. S. Summers: 



River system consequent on the extension of tlie length of the 

 river owing to the formation of the ooastal plains of South 

 Australia. This being so, it follows that this area was fo'rmerly 

 part of an extensive peneplain, the somewhat irregular surface 

 of the country at that time consisting of the older palaeozoic 

 rocks with only a small proportion of alluvium. The building 

 up of the country would be gradual, and the various streams 

 would constantly change their beds, so that bands of sand and 

 gravel should be found in various parts of the alluvial deposits 

 indicating formieo" stream channels. A considerable amount of 

 the reclamation would be due to deposition of fine silt during 

 flood times, so that the general structure of the alluvial deposits 

 would consist of irregularly bedded clayey material, with 

 " horses " of coarser material foi'med along former main stream 

 courses. 



In any channelling Avhich 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 vmderground 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 gravel 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. 



SUAIMART. 



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. 



