174 BLANFORD : GEOLOGY OF WESTERN SIND. 



west of the spot where the line of fracture just mentioned enters the 



Nari beds, there is a peculiar hollow, shaped like an amphitheatre, about 



2 miles across in each direction, cut out of the scarp, and having an 



outlier of Gai beds to the north-east. This hollow 

 The " Bill." J 



is known as « BUI " (Plate VI, fig. 2). The rocks 



below the Gaj beds on the top of the scarp consist of horizontal, or nearly- 

 horizontal, soft sandstones and sandy shales (c), several hundreds of feet 

 thick, having a coral zone at the top (perhaps the same as that found at 

 the base of the Gaj beds near Mugger Peer) . In the low broken ground 

 east of the scarp, the beds continue nearly horizontal for some distance, 

 then gradually turn up with a westwardly dip, and coarse sandstones, 

 (b) brown and yellowish-brown in colour, false-bedded and partially cal- 

 careous, crop out. These pass down into the lower Nari yellow Orbi- 

 toides limestones and marls (a), with sandy beds interstratified. Clypeaster 

 is common in some of the Orbitoides limestones. The lowest bed seen 

 is a dark-grey limestone (a). Then there is much crushing and some 

 faulting, and then east of the fault the soft sandstones re-appear. 



Amongst the lower Nari beds, the sandstones (b) much resemble the 

 fossiliferous beds, with Nummwliies and Orbitoides, seen north of Tong, 

 resting unconformably on yellowish limestones with large white Orbitoides; 

 but none of the ordinary Nari fossils were found in these beds in the 

 section east of the Bill. 



Farther north the fault, now becoming well pronounced, runs along 



the eastern side of a ridge called Piro (Piero of 



the map) crossed on the road between Tong and 



Baili. East of the ridge are the Nari beds already noticed as dipping 



westward in the valley west of the Dumbar range, whilst the Piro ridge, 



towards which these Nari beds are dipping, palpably consists of Khir- 



thar beds, also dipping westward. But the Khirthar beds here differ 



considerably from those of the Khirthar and even of the Dumbar range. 



The latter are the usual massive grey and white limestones, but on the 



Piro range, brown and brownish-yellow limestones in thin beds, with grey 



and white argillaceous limestone interstratified, are the only beds seen. 



To the westward, moreover, these limestones pass under thin beds 



( 174 ) 



