60 BLANFORD : GEOLOGY OF WESTERN SIND. 



of pebbles brought down by a stream which occupied in upper Manchhar 

 times the same position as the Gaj now does. A similar increase in the 

 development of conglomerate near the course of the present rivers has 

 been noticed in the case of the Sub-Himalayan Siwaliks. It is, 

 however, manifest that a great part of the disturbance which has caused 

 the elevation of the Khirthar range is of later date than the Manchhar 



Disturbance of tertiary conglomerate, because that conglomerate has been 

 groups- tilted up at high angles, and appears to dip con- 



formably with the older tertiary rocks. Nevertheless it is true that, as 

 has been shown in the last paragraph, there must have been some change 

 of level before the Manchhars were deposited, and it is also true that there 

 is in places an apparent passage from the upper Manchhar conglomerate 

 into the gravels of the slope, on the edge of the alluvium ; but the latter 

 may simply be due to the reconsolidation of pebbles derived from the 

 conglomerate itself ; and if the amount of disturbance in the interval 

 between the upper and lower Manchhar periods was considerable, the 

 evidence of such a break should be more conspicuous than it is. On the 

 whole, it appears probable that the great period of disturbance which 

 terminated the tertiary epoch in Sind commenced during the deposition 

 of the Manchhar beds, or perhaps even earlier, but that greater changes 

 took place after the highest Manchhar strata had been deposited than 

 during the period of their deposition. 



In one case a few estuarine fossils were found, near the Nari stream, 



Estuarine fossils in m a Manchhar bed 300 or 400 feet above the base 

 Manchhar beds. £ fa e g r0U p_ The only form recognized was 



Corhula trigonalis, already mentioned as characteristic of the estuarine 

 passage beds between Gaj and Manchhar. With this exception, and 

 that of some rolled oyster-shells possibly derived from a lower formation, 

 no marine or estuarine fossils have been observed in the Manchhar beds 

 of Upper Sind, above the passage beds at the base of the group, and 

 there appears every reason to believe that these rocks are of fluviatile origin. 

 The form of the pebbles in the conglomerate of the upper Manchhars 

 is that of stream-worn, and not that of sea- worn fragments ; they 

 ( 60 ) 



