GEOLOGICAL FORMATIONS. 53 



minifera, because they are so abundant and characteristic, yet every 

 Difference from Khir- species is distinct from those occurring in the 

 thar fauna. Khirthar group. Whole beds of limestone towards 



the base of the Nari group are entirely made up of Nummiilites garan- 

 sensis, N. sullcevigata and Orbitoides papyracea, the last-named fre- 

 quently of large size, some specimens being 2 to 3 inches in diameter. 

 One of these species of Nummulites, N. garansensis, is of importance, 

 because it occurs in Europe, as in Sind, in the highest strata character- 

 ized by the abundance of the genus, those beds being at the base of the 

 miocene. Niimmulites sullaevigata is peculiar, so far as is known, to India. 

 Several of the Mollusca and Echinodermala of the Nari beds also, 

 such as Siliquaria gfanti, Solarium affine, Venus granosa, and Clypeaster 

 profundus, show distinctly miocene affinities, and some of these pass up 



into the Gaj group. But at the same time 

 Miocene affinities. 



there are so many eocene forms present, such 



as Natica patula, N. sigaretina, Ostrea fldbellula, Voluta jugosa, fyc, 



that it is somewhat difficult to decide to which sub-division the Nari 



beds should be assigned. They may, perhaps, occupy an intermediate 



position, similar to that of the oligocene of continental geologists. 



6. Gaj group. — Upon the Nari group, almost throughout Sind, there 



, , is found resting a mass of highly fossiliferous 



General character. . ^ 



limestones and calcareous beds, usually more 



or less shaly, always distinctly stratified, and easily distinguished from 



the limestones of the older tertiary formations by the absence of num- 



mulites. A superb section of the strata forming this group is exposed 



on the banks of the Gaj river, the stream which, as already mentioned, 



cuts its way through the Khirthar range south-west of Mehar, and in 



the neighbourhood of which, west of the range, the fine section of 



lower tertiary and cretaceous beds already noticed is exposed. From 



this river the present group derives its name. 



On the eastern flanks of the Khirthar range in Upper Sind, the 



Gaj group forms a conspicuous ridge, the hard dark-brown limestone 



bands near the base of the formation resisting the action of denudation 



( 53 ) 



