128 BLANKMID : GEOLOGY OF WESTERN S1ND. 



about 2,000 feet thick, trap 40 to 90 feet, and the infra-trappeau series 

 classed as cretaceous, of which about 1,400 feet are exposed, the list of 

 geological groups in Sind should be consulted. 1 In the accompanying 

 map, owing to the very small scale, only the Ranikot beds and the cre- 

 taceous rocks are separately coloured, the narrow band of Deccan trap 

 being omitted. The thickness of the Khirthar limestone in the Tiyun 

 range (the ridge running south-east from Dharan), cannot be great, but 

 it has not been precisely determined. A little farther south it is only 

 450 feet on the scarp west of Barrah Hill, and nearly the whole thick- 

 ness is here exposed ; there cannot be much more than 500 or 600 feet 

 altogether. 



Beneath the Khirthar group* on, the eastern scarp of Tiyun, there 



is found a considerable thickness of yellow lime- 

 Highest Ranikot beds. 



stone, which probably represents the brown lime- 

 stones of Lainyan to be described presently. Farther south, near 

 Barrah, the yellow limestone is wanting, having probably been de- 

 nuded away; for throughout this range there is unconformity be- 

 tween the Ranikot beds and the Khirthar. A bed abounding in a 

 species of Rostellaria, apparently the R. columbaria, Lam, of D'Archiac 

 and Haime, but a very different form from the true B. columbaria 

 of Lamarck, is found at Barrah as well as farther north, and is 

 met with some distance below the fossiliferous brown limestone of 

 Lainyan. 



The Ranikot beds and the cretaceous rocks beneath them are well 



exposed from top to bottom under Jakhmari and 

 Section at Jakhmari. . . 



Kharguzani peaks, but all the upper portion is 



much obscured by talus from the overlying Khirthar limestone, and 

 no complete section can be measured. The following is the series of 

 the bottommost Ranikot beds, in descending order, with the under- 

 lying olive shales or Carclita leaumonti beds. The section across the 

 range at Jakhmari is shown in the accompanying section (Plate V, 



fig..l). 



1 See p. 32. 

 ( 128' ) 



