NEGRAIS— NBIAR. 8*T 



Mallet (Man. Geol. Ind., Part IV, Mineralogy, 1st. Ed., 19) be- 

 lieves this to be simply ferruginous blende. 



Newer or Overlying trap.— The name given by T. J. Newbold (Journ. 

 Boy. As. Soc. IX, 1814-1848) to the lava flows now generally 

 known as the Deccan Trap. Newbold regarded the Trap as Ter- 

 tiary in age (Ibid., Vol. XII, 84) formed between the deposition 

 of the " freshwater limestone " (Lametas) and the development 

 of laterite. 



Nga-tha-mu beds.— Described by W. Theobald (Mem., Geol. Sun., 

 Ind.. X. "277. 1873) as occurring on Koranji island and adjoining 

 portion of the Arakan coast near the village of Nga-tha-mu (16° 

 30' ; 93° 49'). The rocks are cream-coloured, calcareous sand- 

 stones, containing fossils similar to some of those in the Gaj 

 beds of Sind. In character the beds resemble in some ways the 

 Porebandar miliolites of the Kathiawar coast. 



Ngwetautlg sandstones.— Name instituted by T. H. D. La Touche 

 (Mem., Geol. Sure, Ind., XXXIX, 66, 1913) for fine-grained brown 

 sandstones, sometimes calcareous, with occasional lenticular bands 

 of limestone, forming the summit of the peak, Ngwetaung, due 

 east of Mandalay. They are of only local development in the 

 Northern Shan States, and fossils are rare. They are considered 

 to be the lowest sub-division of the Ordovician. 



Nilgiri or mountain gneiss.— Proposed by W. King (Mem., Geol. 

 Surv., Ind., XVI, 125, f. n., 1880) for rocks of the kind that pre- 

 vail in the Nilgiris, and other high ranges of South India and 

 Ceylon. These rocks were later described as the charnockite series 

 (q. v.) and are characterised by the constant occurrence in them 

 of hypersthene and other pyroxenes ; they are typically blue- 

 grey in colour, slightly foliated, compact and fresh. They form 

 the chief mass of the Nilgiris, Palnis, Travancore hills, Shevaroys 

 and hills near St. Thomas' Mount, Madras. For these rocks R. 

 B. Foote afterwards used the term Salem gneiss (Mem., Geol. Surv. , 

 Ind., XXV, 30, 1895). 



Nimar sandstone.— Named by P. N. Bose (Mem., Geol. Surv., Ind.* 

 XXI, 3, 23, 1884) and regarded as probably Lower Cretaceous 

 in age. Regarded by H. B. Medlicott (Mem., Geol. Surv., Ind., 

 XXI, 1884, preface to part 2, pp. vi-viii) as part of the Upper 

 Gondwana system of Jurassic age. These sandstones were after- 

 wards sbown by E. Vredenburg (Genl. Report, Geol. Surv., Ind., 



