STRATIGRAPH1CAL ELEMENTS: TRIAS. 2j 



evidently belonging to this horizon they say, " We have found no 

 sufficient reason to suppose its breccias or other beds traceable to 

 volcanic action, as has, perhaps, been supposed by Dr. Verchere." 1 



The position also of these beds, though provisionally assumed 

 to be at the top of the Infra-Trias, is acknowledged by Waagen and 

 Wynne to be equivocal, inasmuch as they may belong to the base 

 of the Trias. 1 shall shew in the detailed sections of Sirban hill 

 that their uncomformity above the Infra-Trias series necessitates 

 their removal from that series and their incorporation with the Trias. 



(2) Upper limestones. 

 The colour of the Trias limestone is generally dark-grey, mottled 



with pale chrome or ochre coloured blotches 

 Colour. 



The latter are in the form of elongated oval or 



vermiform figures. Sometimes the colour of the limestone approaches 



more nearly to a deep purple with occasional bandings of deep yellow 



coloured courses. It is occasionally of a pale blue-grey tint when 



it becomes difficult to separate it from some of the limestones of 



the Nummulitic series. A few spheroidal ferruginous concretions, 



about \ inch in diameter, are found in the Trias limestone of 



Wijjiyan. 



The rock is very massive and thick-bedded, but it is not so evenly 



bedded as the Infra-Trias. It very rarelv 

 Structure. . , , J J 



forms dip-slopes. It weathers into much darker 

 and more sombre colours than the Infra-Trias, which has a marked 

 tendency to weather white or pale grey. 



Minute traces of comminuted shells sometimes run in lines 

 through the rock, but they are too much bruken as a rule for identi- 

 fication. A minute oolitic structure is characteristic of much of the 

 Trias limestone. 



In composition the rock is an ordinary slightly sandy limestone 



without any dolomitic tendency. The thick 

 Composition. . . 



zones of massive dolomite with laminae of 



1 Journ. As. Soc. Bengal, Vol. XXXVI, p. 29, 1867. 



( 27 ) 



