18 OLDHAM : GEOLOGY OF MANIPUR AND NAGA HILLS. 



seem too elevated to have formed a continuous terrace with that to the 

 south of the thanna. 



38. This terrace might not unnaturally be taken as marking an old 

 Not lacustrine high high-level littoral deposit of a lake, once filling the 



level deposits. yaJley q£ Manipur ^ but not only ig itg texture nofc 



such as would be expected in lacustrine deposit, being not unlike that of 

 the so-called ' morraines ' of the Naga hills, and not only does it show in 

 places near its very base evident signs of rivial action in its stratification 

 and false bedding, but, were this explanation admissible, corresponding 

 terraces should be found in all the other valleys draining into the same 

 basin ; so far from this being the case, I have seen no other similar ter- 

 race, in the valley of the Laimakhong there is no such feature, nor so far 

 as could be detected in a distant view from Thunion is there any in the 

 Iril valley ; in both of these, as in all the small ravines flowing from the 

 hills round the Manipur valley, the alluvium extends right up to the foot 

 of the hills which descend in an even slope without any trace of a terrace. 

 The only apparent exception that I can trace is in the Khongba valley ; 

 this I did not see myself, but a sketch is given by Major Godwin- Austen 

 in which a most marked terrace is shown on the east of the valley ; but 

 from the appearance of the sketch and from the descriptive remarks in 

 the text, I cannot but believe that Khongba is here a clerical error for 

 Tiki. 



39. Since then this feature is not general no general explanation is 



„ . . possible, but we must look to a local cause, which 



Cause of origin. ' iil ^" 



I take to be the same as that of the high level 

 deposits of the Naga hills, that in past times in consequence of a colder 

 climate, whether due to elevation or actual climatic change, the amount 

 of debris brought down from the Koupru ridge was vastly greater than 

 at present and choked up the whole valley, a subsequent rise of tem- 

 perature causing an increase of vegetation and decrease of denudation 

 enabling the Tiki once more to cut down the level of its bed. The 

 open tract of low land north of Kaithamabi, which Major Godwin- 

 Austen regarded as a filled-up lake, I take to be due to the almost 

 ( 234 ) 



