OLDHAM : GEOLOGY OF MANIPUR AND NAGA HILLS. 9 



of the district examined in a general north and south direction, is a 

 u characteristic dark-coloured serpentine ; it frequently becomes a gabbro 

 and contains bronzite, and is intersected by veins of gold-coloured chryso- 

 tile, or sometimes carbonate of magnesia ; " the former was not found by 

 me in Manipur. " The hills formed of serpentine may be distinguished 

 at a distance by their barrenness ; they appear to support little except 

 grass and a few bushes. " " In the neighbourhood of some of the larger 

 masses of serpentine, the sandstones and shales are converted into green- 

 stone and chloritic schist ; but the effect varies, and in some instances 

 the neighbouring rocks appear almost unaltered." All this is as true, 

 word for word, of the serpentine of Manipur as of that in Pegu, and suf- 

 fices to show the close similarity, if not identity, of the two which in hand- 

 specimens are undistinguishable — a specimen brought from Burma by 

 Mr. Theobald might, so far as appearance goes, have been broken off the 

 same block as one brought by me from Manipur. It is further worthy of 

 note that the mode of occurrence of this serpentine is the same as in 

 Pegu, namely, that the serpentine outburst is confined not merely to 

 east of the main range, but to the neighbourhood of the eastern limit 

 of the hill rocks. 



18. The date of this intrusion is, as I have already mentioned, posterior 



to that of the rocks to which I have assigned a 

 Date of outburst. . 



triassic age, possibly also to those to which a 



cretaceous age has been attributed, and it is worthy of notice as an addi- 

 tional evidence that these rocks in which it is intrusive are not of 

 nummulitic age that in Pegu the trap is nowhere found intrusive in 

 rocks of undoubtably nummulitic age, and is hence probably of pre- 

 nummulitic age. 



19. The upper tertiaries are almost entirely confined to the borders of 



the region under consideration ; the tract of them 

 Upper tertiaries. 



crossed on the road from Cachar to Manipur consists 



of argillaceous sandstones, sandstones and shales with a north- 10°-east and 



south- 10°- west strike ; after leaving this band I did not again see the upper 



tertiaries to the east till the Angoching and Kasom ranges were reached. 



( 225 ) 



