GEOLOGICAL FORMATIONS. 51 



in thickness to the westward, and the Habb valley, from the spot 



Present in Lower where the river first forms the boundary of British 



territory to the sea, consists entirely of these strata. 



There is, however, in this part of the country, no longer any such marked 



distinction between the sub-divisions of the tertiary series as is found in 



the Khirthar range. The disappearance of the Khirthar limestone has 



already been mentioned, and with it the lower Nari limestones with 



_ Nummulites garansensis and N. sublaviqata also dis- 



Passage into Khirthar. 



appear, so that it is no longer possible to draw 



a distinct line between the two groups, for the shaly beds at the base of 



the Nari group are undistinguishable from similar rocks in the Khirthar 



The calcareous shales, with the characteristic Khirthar nummulites, below 



and the massive Nari sandstones above, are still recognizable, and the 



two groups can consequently still be traced, although the dividing line 



between them is obscured. Beds of brown limestone, too, full of Orbi- 



toicles papyracea (O.fortisi), — a fossil closely resembling a nummulite, and 



associated in abundance with N. garansensis in the typical lower Nari 



limestones, — occur in the Nari beds of the Habb valley ; but instead of 



being found at the base, they appear in the middle of the group. Ao-ain 



just as at the base of the Nari beds there is a difficulty in distinguishing 



them from the Khirthar, so the beds at the top of the former group can 



only be separated by an arbitrary line from the overlying Gaj beds. In 



. . „,.t. 3 tne Khirthar range, the upper boundary of the 

 Passage into Gaj beds. . " L± J 



Nan group, although there is no unconformity, 

 is distinct and definite, limestones with marine fossils of the Gaj group 

 resting immediately upon the upper Nari sandstones. But in Southern 

 Sind bands of limestone, or calcareous sandstone, with marine fossils, 

 some of which are well-marked Gaj species, occur in the upper part of 

 the Nari group, whilst limestone bands_with the Nari OrUtoides jpapyracea 

 are found in the Gaj. 



The sandstones, which form so large a portion of the Nari group, 

 have hitherto proved destitute of animal remains, and in the typical 

 area in Upper Sind, no beds with marine fossils are intercalated in 



( 51 ) 



