C OLDHAM : GEOLOGY OF MANIPUR AND NAGA HILLS. 



lity in favour of these suppositions is greater than that against them, 

 we have a most decided case of overlap. Further, on the western slope 

 of the hill on which Chamu Kulel is situated, and again both north and 

 south of the Kayeng village, white shales are found; I am not prepared 

 to identify these for certain with the indurated pipeclay of Chatik, but 

 they are very possibly the same ; if so, their occurrence in these positions 

 is still further proof of overlap. 



11. Besides this more or less direct evidence, there is the indirect evi- 

 Indirect evidence. dence of the contemporaneous volcanic deposits 

 Volcanic ash. near Kachao, which being from their nature and 



composition probably derived from the same source as the great trappean 

 intrusion of the neighbourhood would naturally be of later date than 

 the rocks in which the latter was intrusive, thus pointing to the presence 

 of rocks belonging to at least two series. Unfortunately this argument 

 is somewhat double-edged, for of all the rocks that I saw few were more 

 metamorphosed than those immediately under the Kasom range, which 

 I have coujecturally identified with the limestone and coloured shales of 

 Kongui. This fact is explicable on the hypothesis that the beds among 

 which the volcanic ash was found interstratified are but higher beds of 

 the same series in which the limestone is near the base ; and bearing in 

 mind the jungly nature of the country, the disturbed condition of the 

 rocks, the paucity of exposures, and the fact that I had not that complete 

 command over my own movements necessary for the proper elucidation 

 of a country having such a complicated structure as that under consider- 

 ation, I am not able either to refute or substantiate such a conjecture. 



12. The facts noticed in the above paragraph may point to a third 

 Possibility of a third series of rocks existing in this neighbourhood 



series " contemporaneous with the serpentine intrusions, 



and newer than either of the other two above noticed. 



13. Having thus, as I believe, proved that the older should be divided 

 Deinarcation of series m ^° a ^ least two distinct series, there remains the 



important problem of where to draw the line 

 between them, and to this I regret to say I see no hope of a solution ; but 



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