54 BLANFORD : GEOLOGY OF WESTERN SIND. 



far more than the soft sandstones of the Nari beds, and rising every 



here and there into peaks of 1,000 and 1,500 

 Kidge of Gaj beds. 



leet, or even more, escarped to the west- 

 ward, and sloping to the east ; Amru, the highest summit of the Gaj 

 ridge, being 2,700 feet above the sea. Still, the limestone bands, 

 although so conspicuous, are subordinate, the greater part of the group 

 consisting of sandy shales, clays with gypsum, and, towards the 

 base, sandstones. Many of the bands of limestone appear very constant 

 in position, and may be traced for a long distance ; as a rule, they are 

 dark-brown in colour, but one bed is white and abounds in corals and 

 small loraminifera (Orbitoides) , whilst some of the darker bands contain 

 EcMnodermata in large quantities. 



The uppermost portion of the group is usually argillaceous, being 



chiefly composed of red and olive clays with 

 Estuarine passage beds 



between Gaj and Manchhar white gypsum, and these beds pass gradually 

 into precisely similar strata belonging to the 

 overlying Manchhar group. The passage beds contain, amongst other 

 fossils, such as Turritetta angulata, and forms of Ostrea and Placuna, the 

 following : — 



Corbula trigonalis. 1 Tellina subdonacialis. 



Lucina (Diplodonta) incerta. ' Area larlchanaensis. 



All cf these have allies living in estuaries at the present day ; Area 



granosa, a recent representative of A. larkhanaensis , being one of the 



commonest and most typical of Indian estuarine mollusca. To these 



estuarine passage beds further reference will be made presently when 



the relations of the Manchhar to the Gaj beds are discussed. 



The Gaj beds at the Gaj river are very nearly 1,500 feet thick, but 



they appear to be less developed to the north- 

 Thickness. . . 



ward 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 pres- 

 sure. 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 

 ( 5* ) 



