OF WESTERN SIND. 275 



The Gaj beds at the Gaj river are very nearly 1500 feet thick, but they appear to be 

 less developed to the northward in the Khirthar range, and not to be much more than 

 half the thickness named west of Larkana, where, however, they are nearly vertical, 

 and have probably suffered from pressure. In Lower Sind the Gaj group, like the 

 Nari, disappears to the eastward of the Laki range, where it is either entirely wanting 

 or else represented by a thin band, containing one of the characteristic fossils, Ostrea 

 multicostata, at the base of the Manchhar group. There is, however, a very large area 

 of Gaj beds north and north-east of Karachi ; and the appearance of the formation 

 there is somewhat different from what it is in the Khirthar range ; for the greater 

 portion of the group consists of pale-coloured limestones, almost horizontal, or dipping 

 at very low angles, and to the east of the Habb valley forming plateaux 400 or 500 feet 

 high, bounded by steep scarps, which rise from the low ground of the soft Nari 

 sandstones. 



" A low range of hills, formed of Gaj beds, extends to the south-west, past the 

 hot springs at Magar or Mangah Pir, to the end of the promontory known as Cape 

 Monze, west of Karachi ; and the same beds form the low hills east and north-east of 

 the town, and furnish the materials of which the houses in Karachi are mostly built. 

 A small island called Churna, in the sea, west of Cape Monze, also consists of Gaj rocks. 

 To the northward, the Gaj area of Lower Sind extends, with very irregular outline, to 

 the neighbourhood of Tong and Karchat, almost due west of Hala ; and there are 

 several outliers farther north, connecting the southern portion of the group with the 

 typical outcrop in the Khirthar range. East of Karachi, also, Gaj beds extend in the 

 direction of Tatta until they disappear with the other Tertiary rocks beneath the 

 alluvium of the Indus. As was shown in a previous chapter, the Gaj group of Sind 

 appears to be represented in Cutch by a highly fossiliferous belt, containing most of 

 the typical mollusca, echinoderms, &c. It is quite possible that the present group, as 

 well as the Nari, never was deposited in the neighbourhood of Kotri and Jhirak. 



" It has been already stated that the Gaj beds, throughout the greater portion of 

 the Khirthar range, rest conformably upon the Nari group, although there is a change 

 in mineral character, and that in Lower Sind the passage from one group into the 

 other is gradual, calcareous bands, with Gaj fossils (such as Ostrea multicostata and 

 Pecten subcorneus), being found interstratified with the uppermost Nari sandstones. At 

 one place, however, near Tandra Eahim Khan, west by north of Schwan, the outcrop 

 of the Gaj beds, here dipping at a high angle to the westlvard, runs nearly in a straight 

 line across the mouth of a valley, composed of a deep synclinal of the Nari group, 

 between two anticlinal ridges of Khirthar limestone. As the Gaj beds do not share 

 the synclinal curve of the Naris, it is difficult to see how the two can be conformable ; 

 but an examination of the boundary between the two groups failed to show any clear 

 evidence of unconformity. There are, however, some places south of Sehwan where 

 the Gaj group overlaps the Nari beds and rests upon the Khirthar limestones ; but it 

 must be recollected that the Gaj group is itself overlapped by Manchhar beds in the 

 immediate neighbourhood. The commonest and most characteristic fossils of this 

 group are Ostrea multicostata and Breynia carinata." 



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