GEOLOGICAL FORMATIONS. 47 



south-east in Cutch 1 , where the whole group consists of comparatively- 

 thin beds of limestone, interstratified with shales. To the south-west, 

 near the Habb river, the massive limestone dies out altogether, and 

 although it is well developed in the southernmost extremity of the 

 Khirthar range, near Karchat, about 50 miles south of Sehwan, it 



_,. „„.. disappears within a distance of 25 miles, 2 



Disappearance or Khir- x x ' 



thar limestone to south- anc l in the ranges on the Habb river is en- 

 tirely replaced by shaly limestone, shales, and 

 thick beds of sandstone. Some rather massive beds of nummulitiferous 

 dark -grey limestone, very different in character from the pale-coloured 

 Khirthar limestone, are found west of the Habb, but their precise 

 position in the series is not known, and the rocks appearing from beneath 

 the Nari group, in the place of the Khirthar limestone, consist of shales 

 and sandstones, with some calcareous bands abounding in nummulites, 

 and closely resembling, both in character and in the species of Foramini- 

 fera they contain, the nummulitic shales beneath the massive limestone- 

 on the.Graj river. It is not known to what extent the typical Khirthar 

 Khirthars in Baluchis- limestone is developed in Baluchistan; around 

 tan * Kelat, to the northward, this band appears to be 



extensively exposed, but to the westward, near Gwadar, the rocks sup- 

 posed to represent the older tertiary beds consist of an immense thickness 

 of shales, shaly sandstones, and unfossiliferous calcareous bands, resem- 

 bling the lower Khirthars of the Gaj and the beds of the Habb valley, 

 and limestones with nummulites are of unfrequent and local occurrence. 

 It is thus evident that the Khirthar limestone, although it is so conspi- 

 cuous in most parts of Sind, and although it attains a considerable thick- 

 ness, is not by any means universally distributed. 



1 Mem. Geol. Surv. India, Vol. ix, p. 11. 



2 In the " Manual," p. 458, the distance was stated to be 12 or 14 miles. This was 

 under the supposition, which is highly probable, that the shaly beds of the Piro range near 

 Baili, west of Dumbar, represent the massive limestones of the Khirthar range. There is, 

 however, a possibility that the shaly limestones of Baili, like those of the Laki range to the 

 east of the Khirthar, are only the uppermost beds of the group, and that the massive lime- 

 stone may occur below. So far as is known, however, on the Habb, the massive limestone is 

 wanting. A great thickness of Khirthar beds is exposed, but all consist of shales, marls, and 

 sandstones. 



( 47 ) 



