AREA SOUTH OF THE SAFSD KOH. I05 



increase, till the series becomes one of shale. It is very difficult 

 to estimate the thickness of this limestone, 



Thickness. . , . ^_ 



but it cannot be less than 2,000 feet. Nor can 



its age be determined in the complete absence of recognisable fossils, 



but it immediately overlies a series of red grits 

 Age- . . . 



and shales, which cannot be older than triassic, 



and it will, therefore, represent the rhaetic and possibly, in part, 



Jurassic. 



Immediately under this limestone series is a great thickness of 



bright red and brown shales, with grits and 



conglomerates. They are well seen on the 



bank of the river flowing from Bcigh, at about J mile south of the 



, , point at which it joins the Bira river. The 



General characters. 



uppermost member is a red gritty shale identi- 

 cal with that already mentioned as underlying the rhaetic limestone 

 at Mir Khan. This shale is underlain by a coarse sandstone 

 in thin bands, interstratified with brownish-red needle shales, the 

 whole succeeded by about 200 feet of fine red needle shale, on which 

 _, , . bed the village of Dwatowi stands. The 



Shales at Dwatowi. 



shales, which here dip at high angles (almost 

 vertical) to the south, are underlain by a thin band of limestone 

 which in turn is succeeded by a series of sandstones and grits, gra- 

 Sandstone, grits and dually becoming coarser till they pass into a con- 

 glomerate composed of large rounded blocks and 

 pebbles of limestone and sandstone, with some gneiss, all embedded 

 in a coarse sandy matrix. Next follow beds of coarse grit and 

 sandstone in rapid alternation, and underlying the whole series 

 ._ ,, . , a bed of brown needle-shale, several hundred 



Needle-shale. 



feet in thickness. I found no fossils in these 

 rocks, but plant markings can be seen in the lowest shales. By far 

 the most extensive member of the series is this needle-shale, which at 

 the head of the B£ra Valley forms rolling downs extending from the 

 BaVa river to the Safed Koh. Owing to the softness of the beds, the 

 river has cut out its course along their outcrop, which can be traced 



( i°5 ) 



