1868.] Proceedings of the Asiatic Society. 233 



A conversation took place in which several gentlemen joined. 



The President said, in concluding the remarks on this paper, that he 

 entirely agreed with Mr. Medlicott, that there was but little of novelty 

 in the paper which had been read. It was a purely local, and simple 

 description of facts ; not pretending to great scientific accuracy. For 

 example, it was scarcely correct to speak of the eroding action of the 

 river as of two kinds, slow and rapid, inasmuch as the action was in all 

 cases of the same kind, and the slowness or rapidity with which the 

 results were produced, depended on the nature of the material acted 

 upon. Again Mr. Wilton Oldham had, in speaking of the l permanent' 

 banks of the river, used the term evidently in rather a general, or rela- 

 tive sense. No bank of an eroding river could truly be called permanent ; 

 still the word was applicable, when the rate of erosion w 7 as so slow, 

 that changes were only traceable after long intervals. But Mr. Oldham 

 had also, in this paper, used the term in a sense somewhat different 

 from that in which it is commonly used. Every river flowing in any 

 alluvial plain, which may be taken as comparatively homogeneous, has 

 for itself at different times, and subject to differences in the slope of its 

 bed, a plain or surface, within the limits of which it tracks its course 

 back and forward, depositing here, and cutting away there, and thus often 

 passing and repassing over the same ground. And so far as general 

 observations are concerned, these limits of oscillation are so slowly 

 changeable, that the banks, limiting the plain of the river, which for 

 the most part become tolerably w r ell marked, may be, and generally are, 

 called the ' permanent' banks, those banks within which (abstracting 

 considerations of external forces) the fall of the river's bed and the 

 amount of water combine to restrain the oscillations of the river. If 

 taken in this sense, the permanent banks of a river flowing in an al- 

 luvial plain, may be generally considered to be composed of similar 

 materials to the country around, and would be, if the river were 

 directed against them, as liable to erosion as any other part of the 

 country. 



But the case stated by Mr. W. Oldham is quite different ; here the 

 permanent banks, he speaks of, are composed of material quite of a 

 different kind and of a greater resisting power. He describes these de- 

 posits as characterized by kunkur, and being of a hard stiff clay. And 



