SATGHAN SERIES. 



31 



rivers— a few miles below Doab-i-Mekhzarin (PI. 5). The lowest 

 bed is a white sandstone, which contains a certain amount of volcanic 

 material. At Ishpushta this bed appears to lie with perfect conformity 

 on the volcanic series, the upper beds of which are grey ashes overlying 

 dark needle shales. The origin of the white basal bed of the plant- 

 bearing series is obscure ; it appears to be an ash deposited in water. 



From the apparently perfect passage found here between the 

 volcanic rocks and the plant-bearing series, it may be inferred that 

 the occasional unconformities between the two represent no particular 

 time-break but are only what would be expected in the change of 

 conditions of deposition. The age of this series has not yet been finally 

 determined, but there is little room for doubt that it is J urassic. The 

 fossil plants collected by me are at present in the hands of Professor 

 A. C. Seward, who has kindly undertaken to describe them. They 

 are to a great extent identical with collections obtained by Messrs. 

 Weber, Nazarow and Bronnikow in Russian Turkistan and recently 

 described by Professor Seward (25) . By Mr. Griesbach they were 

 regarded as Triassic on account of his discovery at Chahil of a band of 

 shale containing lamellibranchs that he determined as Daonella lommeli 

 Wiss. and Monotis salinaria Schloth. 



He recognises three principal horizons (9, 245) which are, in des- 

 cending order — 



(c) Sandstone and shale with Schizoneura. 

 (b) Sandstone and shale with Equisetites columnaris. 

 (a) Calcareous sandstone, with Monotis salinaria and Halobia 

 lommeli. 



Coal seams are stated to occur between (a) and (b) and (b) and (c). 

 Some importance attaches to Mr. Griesback's observations on these 

 Chahil beds, since this is one of the localities at which he believed that 

 he had found Gondwanas, and Professor Suess has embodied this view 

 in his account of the Hindu Kush (29, 292). Too much weight should 

 not be attached to this tentative classification, however. Mr. Griesbach 

 states that his highest horizon (c) has " a strong resemblance to Upper 



