STRATIGRAPHICAL ELEMENTS: JURASSIC. 31 



talus of hard abrading fragments, the Spiti shales give no ring> 

 and weather into soft paper-like laminae, or into black clay. 



2. Whilst they have such a great extension along the general 

 strike of the Himalaya, keeping the same lithological features as 

 far as Kumaun, a distance of about 480 miles, they rapidly change in 

 a southerly direction (see infra, page 32), and are quite unknown in 

 the Salt-Range, although rocks of Jurassic age are known through 

 these areas. In Kashmir, rocks of Jurassic and also of Cretaceous 

 age are unknown ; doubtless they have been overlapped by the Num- 

 mulitic formation ; but it is reasonable to suppose that, saving the 

 overlap, Spiti shales of the usual character would have been found 

 there uniting the Hazara and Spiti areas. 



3. Thin friable shales occur higher up in the geological record 

 among the Nummulitic formation, but their colour is pale grey, 

 buff, or ochre, whilst their lamination is never so perfect. 



The Spiti shales, therefore, considering their lithological charac- 

 ters alone, are a unique deposit, as recognisable over large areas as 

 the Kimmeridge clay of England; but their extension is a strike 

 extension only, with a very rapid change in the opposite direction in 

 Hazara. 



They do not appear to have been recognised by Verchere ; nor is 

 this to be wondered at, since in his section near Shakur Bandeethey 

 are hidden by gravels except up towards the higher parts of the 

 ravine above the town. 



Continuing the petrological description of the northern sections 



of the Jurassics in Hazara, we note first a 



Gieumal sandstone. gradual passa g e by interbedding from the Spiti 



shales into the next stage, the Gieumal sandstone, which like the 



former takes its name from the Spiti area. 



The Gieumal sandstone is an extremely characteristic rock. 

 In colour it varies from a dark olive-green to a dark grey almost 

 black rock, trappoid in appearance. The sandstone weathers at 

 the surface into a brown layer, extending sometimes an inch or more 

 into the rock. At Sha-ala-ditta the rock is banded dark reddish- 

 brown and dark greenish-black. 



( 3" ) 



