14 THE FOSSIL CORALS AND 



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 direc- 

 tion 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 

 moUusca, 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 sulcorneus), being found interstratified with the uppermost Nari sandstones. At 

 one place, however, near Tandra Rahim Khan, west by north of Sehwan, the outcrop 

 of the Gaj beds, here dipping at a high angle to the westward, 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 imme- 

 diate neighbourhood. The commonest and most characteristic fossils of this group are 

 Ostrea multicostata and Breynia carinata. There cannot be any question that the Gaj 

 fauna is newer than Eocene : some of the species are recent (for instance, Bosinia pseu- 

 doargus is identical with the recent B. exasperata, Chemn.) ; and it is probable that 

 many others, when they are compared with recent forms more carefully than has 

 hitherto been done, will prove to be the same as living species. Several genera, too, 

 as Maretia, Breynia, Meoma, Hchinodiscus, Cladocora, and Bchinopora, are rare or un- 

 known in the older Tertiaries ; and there is almost a complete disappearance of Eocene 

 forms, very few species being common to the Nari beds even. The chief doubt is 

 whether the Gaj should not be considered as Upper Miocene. The only mammal yet 

 obtained from the Gaj beds is Rhinoceros Sivalensis, a species found also in the Siwaliks." 



IV. The Classification followed and the Works consulted. 

 The classification followed in this Monograph of the fossil Corals of Sind is 

 principally in accordance with that of MM. Milne-Edwards and Jules Haime, and 



