NUMMULITIC SERIES. 17 



The area described by Captain Godwin- Austen^ in the neighboui*- 

 hood of the Umblai, the boundary of the Khasia and Garo districts^ 

 seems in every respect to be a most interesting- one. It corresponds 

 with a remarkable depression extending- right across the plateau ; and 

 there seems to be a local development of some groups of the sedimen- 

 tary series. Some striking instances of irregularity in the nummulitic 

 deposits are noticed : in one section^ within a short distance^ a distinc- 

 tive top run of limestone passes on to the cretaceous sandstone^ over- 

 lapping some 300 feet of lower limestone beds. 



Upon the few nummulitic fossils I was able to procure^ Dr. 

 Stoliczka has given the following note : " Lairungao^ the northernmost 

 limit of the limestone ; — a bluish gray compact limestone^ some of it 

 consisting entirely of little fragments of various shells^ in a calcareous 

 cement, Operculina eanalifera, D''Arch.j and NummuUtes Lamarchi, 

 D^Arch.j are very common ; besides these — fragments of a TrocliocyatJius; 

 Styloccenia Vicaryi, Haime ; Echinolampas spheroidalis, D''Arch., a small 

 Cardita ; Pecten j Natica RouauUi, D^'Arch ; Keilostoma marginatum, 

 Lam. ; a ZizipMmts ; the small Cerit/iium KooTceri, D^Arch., casts of a 

 larger Natica, CeritUum, Terebellnm, etc. Cherra Piinji — limestone like 

 the last, portions consisting almost entirely of small specimens of 

 O'p. eanalifera ; Num. Lucasana and Num. Ramondi, both the last species 

 very small ; there are also species of Echinoids, fragments of Oysters, 

 and Pecten, Cardium Salteri, D^Arch. ; and various fragments of Natica, 

 CeritUum, Turritella and others. Those portions of the limestone 

 which consist chiefly of shell fragments generally do not contain many 

 Nummulites; these occur gregarious in separate masses. 



" The earthy limestone of Ryak on the Sumesari in the Garo dis- 

 trict is almost made up of a mass of Num. granulosa, D^Arch., in various 

 stages of growth.^^ 



* Jour. Asiat. Soc, Bengal, Vol. 38, Pt. 2, p. 1, 1869. 



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