so 



covered "by a slieet of tard brittle material of an eiglitli to 

 one-fourth incli tMck, constituted of the disintegrated calci- 

 ferous sand cemented by common salt. An analysis of 40 

 grains dried at 100° C. yielded 16'28 grains of common salt 

 extracted by distilled water and weighed after heating to red- 

 ness. A portion of the calciferous sand-rock, taken from 

 beyond a few inches of the surface, yielded the following : — 

 Salts extracted by boiling water ... ... 0"4 



Salts dissolved by hydrochloric acid* ... 11"1 

 Insoluble residue ... ... ... ... 88'5 



1000 

 It is, therefore, no longer a matter for wonder that the pent- 

 up waters within the alluvium are brackish. 



In no instance in the lower section of the river do the walls 

 of the gorge approach so closely as to confine the river, and 

 very rarely are the alluvial flats in opposition, the rule being 

 that the river flows along one side of the gorge for a more or 

 less straight course of varying lengths, whence it gradually 

 curves inward, and finally impinges on the opposite wall ; so 

 that cliff and alluvium confine the river alternately on the one 

 side, and alluvium and cliff on the other. 



The course of the river is not so circuitous in this section as 

 it is in the upper, where the river for long distances meanders 

 through the alluvium ; and here the course of the river is 

 undergoing rapid change. The concave bank is continually 

 being worked upon by the falling waters, whilst considerable 

 deposition takes place on the corresponding convex-face. In 

 some instances the periodic extension of the alluvium is dis- 

 tinctly marked by lines of red gum trees, graduating from 

 saplings near the water's edge to full grown trees at several 

 chains inward. 



Oeiqin of the Goege of the Eivee. 

 I think it will be conceded by all who have thoughtfully 

 examined the rocky walls between which the river flows that 

 they were once continuous, and that their separation is the 

 result of the wearing action of the river itself. I am also of 

 opinion that the gorge from Overland Corner to "Wellington 

 was at one time occupied by a stream covering its whole 

 breadth. The irregularities of the gorge might be explained 

 by the contour of the original surface and the varying degree 

 of hardness of its rocky material rather than by the variability 

 of the rock structure at present water-level, though the latter 

 circumstance might have operated to form the minor sinuosi- 



* Determined by difference. 



