SOUTH-WESTERN PORTION OF KARACHI COLLECTORATE. 159 



abounding in the tubes of Kuphus rectus, together with a minute 

 Fibularia and an Echhwlampas. In one place there are a large number of 

 dark-coloured calcareous concretions containing casts of a Cerithium closely 

 resembling G. pseudocorrugatiim. It is by no means certain whether 

 this bed should be classed as Nari or Khirthar. On the west side a 

 white limestone, abounding in microscopic Foraminifera, is seen cropping 

 out from under whitish limestones with Nummulites garansensis and N. 

 sublavigata. Above these white limestones are ferruginous sandstones 

 of Nari age. The difficulty of distinguishing between Khirthar and 

 Nari beds in this area is as great as it is 30 or 40 miles further north 

 near Maliri, but the reason is different ; to the northward the upper 

 Khirthar beds resemble the lower strata of the Nari group, whereas, 

 near Bhule Khan's Thana, and also in many places to the westward ; there 

 are white limestones at the base of the Nari group closely simulating 

 the underlying Khirthar beds. 



The valley, through which the hill road runs from Sehwan to Karachi, 



Valley south of Bhule continues to the southward after the Baran river 



Khan's Thana. jj ag cu ^ ^ g wa y ^ ^e eastward through the 



Laid range. But south of this the valley becomes less defined, the hills 

 to the westward south of the Kambu ridge are no longer continuous, 

 but broken up into small north and south ranges, and the Laki range 

 itself only continues along the eastern side of the valley for about 12 to 

 15 miles south of Bhule Khan's Thana ; the country then becomes 

 more open, and the road to Karachi turns westward, and soon enters the 

 great Gaj area to be described presently. 



In the plain around Bhule Khan's Thana most of the small rises 

 G" b d Bhul which appear above the subrecent gravels and sands 



Khan's Thana. are composed of Gaj beds, usually fossiliferous, 



the commonest fossils being Ostrea multicostaia and Breynia carinaia. 

 The beds are brown calcareous and ferruginous sandstones. Such are 

 seen just west of the Baran pass (the Durwat) on the road from Bhule 

 Khan's Thana, resting unconformably on Khirthar nummulitic lime- 

 stones. 



( 150 ) 



