46 
HAYDEN : GEOLOGY OF SPITI. 
passes over a mass of dolerite which has been intruded along a fault 
running at right angles to the strike of the shales and quartz ites. 
This point is one of considerable importance, for the supposed existence 
of contemporaneous trap-flows in these beds in Spiti has been used as 
an argument in favour of their correlation with Lydekker's "Panjal, 
Normally, then, the series overlying the carboniferous limestones 
consists of dark shales and quartzites : in the lower part of the series 
shales predominate, but towards the top the two rocks alternate rapidly 
and the quartzite bands increase in thickness, till the series becomes 
one of quartzite and grit — often calcareous —with thick beds of coarse 
conglomerate ; these pass up into a gritty, calcareous sandstone, from 40 
to 150 feet thick, overlain by a bed of black and dark brown 
shale (the " Productus shales "). The two last-named beds — calcareous 
sandstone and Productus shales — are invariably present throughout 
Spiti and Bashahr, and constitute the uppermost members of the 
palaeozoic group. As already stated, they are in most sections uncon- 
formable to the beds on which they rest, but in the northern parts of 
Kanaur, and in upper and lower Spiti, the underlying beds occur in 
their fullest development, and there is no evidence of unconformity, 
for the conglomerates pass up gradually, through calcareous grits, into 
the calcareous sandstone. 
The complete sequence of the upper palaeozoic systems is therefore 
as follows : — 
system " of Kashmir. 
5. Productu? shales : 
4. Calcareous sandstone : 
3. Conglomerate, grit and quartzite : passing down 
• Permian. 
into 
2. An alternating series of shale and quartzite : 
I. Limestones and quartzites of the Lipak river. 
