OLDHAM : GEOLOGY OF MANIPUR AND NAGA HILLS. 5 



anticlinal fold of the rocks, and though from my own observations alone 

 it would he impossible to decide which, we have fortunately the observa- 

 tions of Major Godwin-Austen who found exposures of limestone, 

 evidently a continuation of the Hungdung exposure, along the Rapfo 

 ridge and as he does not mention any limestone to the east of this we 

 may conclude that the corresponding exposure is separated by a greater 

 intervening distance than is the case in the Nung-shong-khong 

 valley. To the south, again, on the Susukameng-Kungal section no 

 trace of the limestone was seen, and, unless some red coloured slaty 

 rocks exposed under Tangkul Hungdung represent them, the red 

 and green shales were equally absent. We have then the two out- 

 crops diverging towards the north ; this might be due either to an 

 anticlinal whose axis had been elevated od the north/or a synclinal whose 

 axis had been elevated towards the south. But, as I shall have occasion 

 to point out when treating of the distribution of the upper tertiaries, 

 there are very strong reasons for assigning an elevation to the country 

 to the south rather than the north of the Nung-shong-khong. We may 

 adopt the latter hypothesis, which would place the limestones above the 

 red shales. Corroborative of this conclusion we have the section under 

 the Kasom range here, where as far as appearances go we have an ascend- 

 ing section from west to east, limestone was found immediately beneath 

 the escarpment of the upper tertiaries, while to the west, and therefore 

 below it, red slates were found ; if, and I see little reason for doubting the 

 conclusion, these beds are identified with those in the Nung-shong-khong, 

 it is another proof of the superposition of the limestone on the red and 

 green shales. 



10. But it still remains to discuss whether these limestones and 

 coloured shales should be considered asbelonging to 

 the great series below them or should be separated, 

 and if so, where the line of separation should be drawn. Now, if the 

 pipeclay of Chatik and that in the Barak valley be on the same horizon, 

 and if the identification of the limestone at Khangoi and Hungdung with 

 that below the Kasom escarpment be correct, and the weight of probabi- 



( 221 ) 



