PERMIAN SYSTEM. 
The characters of the Productus shales and the underlying cal- 
careous sandstone are so constant throughout Spiti and Bashahr that 
descriptions of other sections would be superfluous. 
With regard to their age, their position immediately below 
Age of Produc- triassic beds, as well as their similarity to the 
tus shales. permian beds of Painkhanda and Johar, prove 
that the Productus shales of Spiti should be included in the pernnati 
system, while their intimate connection, both stratigraphically and 
palaeontologically, with the underlying calcareous sandstone, favour 
the inclusion of the latter in the same system, but where the base 
of that system lies cannot be decided till the Spiti collections have 
been worked out in detail. For the present, it is only possible to say 
that the Productus shales are certainly permian and the calcareous 
sandstone and conglomerate series almost certainly so. 
In the Salt Range Xenaspis carbonaria and Cyclolobus oldhami 
were described by Waagen from the upper Productus limestone, but 
more recently Dr. Noetling has placed the zone of X. carbonaria 
in the upper part of the middle Productus limestone and that of 
Cyclolobus oldhami considerably higher up, in the upper Productus 
limestone. Waagen's original specimens of these two species were 
obtained from the same band in the upper Productus limestone,* and 
hence this zone may not improbably correspond with the zone of 
Xenaspis cf. carbonaria and Cyclolobus cf. oldhami in the Pro- 
ductus shales of Spiti. The lower part of the Productus shales 
would therefore correspond in part to the lower part of the upper 
Productus limestone and probably also to part of the middle Productus 
limestone. 
The underlying calcareous sandstone has been correlated by 
Dr. Noetling with the middle Productus limestone of the Salt Range* 
The following table taken from a more comprehensive one pre- 
pared by Dr. Noetling ^ shows the correlation adopted by him 
• 
1 Pal. Indica, ser. XIII, vol. I, p. 25. 
* Neues Jahrbuch fiir Min., etc., vol. XIV, 1901, p. 444. 
^ Ibid., opposite p. 468. 
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