SOUTH-WESTERN PORTION OF KARACHI COLLECTORA.TE. 161 



close by, to the eastward, a small strip p£ G£j beds is seen, containing 

 JEchinodiscns and other fossils, dipping towards the Nari beds to the west- 

 ward, and probably faulted against them. Beneath the Gaj beds, which 

 occupy an insignificant area, are Nari rocks with Nwnmulites garansensis , 

 Orbitoides papyracea, the large Echinolampas , Naticapatula, Pecten labadyei, 

 &c. The upper Nari beds are consequently wanting here, and the group 

 cannot be more than 200 feet thick, as Khirthar beds appear in the 

 Watwaro range a little farther east. This affords evidence that there is 

 a gradual thickening of the Nari beds to the westward, whilst they are 

 wanting to the eastward. 



The large plain, with scattered low rises, extending from the 



Khirthar limestone southern extremity of the Laid range, near Trak, 



area south-east of Irak. to the railway between Jhimpir and Jungshahi, 



has afforded no features of interest. The nummulitic limestone (Khir- 

 thar) of which the area is composed, is nearly horizontal. At one place, 

 between 7 and 8 miles east-by- south of Trak, and about 3 miles from 

 Kalla (Kael), an "Armenian bole quarry " is marked on the 1-inch 

 Revenue Survey map. The rock, at the spot, is nummulitic lime- 

 stone, interstratified with which is a bed, about <J feet thick, of clay or 

 fuller's earth, olive or brownish-olive in colour. The interstratification 

 of this clay with the Khirthar limestone is important, because similar 

 clays found underlying the nummulitic limestone south of Rohri were 

 at first ascribed to an older formation. The limestone contains Nummu- 

 lites granulosa, N. leymeriei, and N. ramondi. The beds around dip at a 

 low angle, and are probably high in the Khirthar group. 



Near Kalla there is a small patch of beds with Ostrea mnlticostata, 

 apparently Gaj. There are probably other small outliers. It was im- 

 possible, without giving much more time than could be spared or than 

 the importance of the geology justified, to map all the intricacies of 

 this country in detail. 



The Kara range, extending from Trak to near Jungshahi, is a long low 



anticlinal ridge of Khirthar beds, with Nari rocks 

 Kara range. 



forming a synclinal to the eastward, and coming 



I ( 161 ) 



