141 DE. E. H. PASCOE OX THE EVBLY HISTOKY [voL lxxv, 



have been recognized, and are practically continuous to Sind, "where 

 they appear to be flu via tile. It is quite possible that a search for 

 vertebrate remains in the Shirani Hills may demonstrate the 

 presence of Murree beds, and so bridge the supposed gap in the 

 belt of these deposits. We may then postulate either a river 

 already established from east of Xaini Tal to Sind, or, following 

 the suggestion made above, a series of lakes and lagoons extending 

 from Simla to the Shirani Hills, into which flowed a river from the 

 direction of Assam, the precursor of the Brahmaputra. At the 

 other end these lagoons were drained by a river flowing through 

 Sind, the precursor of the Indus. Finally, towards the end of the 

 Murree epoch, the whole line of lagoons and lakes were drained, 

 and' gave place to a river. The river connecting the old lake- 

 system with the Arabian Sea was meanwhile submerged to form an 

 estuary, in which were deposited the Gaj Beds of Sind. This 

 estuary finally silted up, and at the beginning of the Siwalik epoch 

 the whole geosynclinal line of depression was, according to the 

 hypothesis that I am advancing, occupied by a river, the Indobrahm, 

 rising probably in Assam, flowing north-westwards along the foot 

 of the Himalaya, from which it received numerous silt-carrying 

 tributaries, and emptying itself into the Arabian Sea, which at that 

 time covered part of Sind. More will be known regarding the 

 distance to which it extended eastwards, when the Assam Siwaliks 

 have received more attention ; but the Himalayan movements must 

 have produced similar effects at this end of the chain, and it seems 

 justifiable to deduce a continuation into Assam of the hydrographic 

 line and, to some extent at least, of the trough. Mr. Oldham 

 gives no geodetic evidence of the latter ; there seems to be a slight 

 sub-alluvial barrier between the Graro Hills and Bhutan, perhaps 

 like that which slightly interrupts the Punjab trough as the sub- 

 alluvial prolongation of the Aravali ridge north-east of Delhi. 1 

 The proximity to the Shan fold- system would explain such inter- 

 ferences in Assam. 



Throughout the whole of the Murree epoch the buckling 

 movement persisted, and the continued depression accompanying 

 it permitted of the accumulation of a great thickness of sediments. 

 This depression seems, in the Murree epoch, to have reached a 

 maximum in the neighbourhood of the obstructive or syntactical 

 point of Mozuffarabad, for the Murree beds are here not much less 

 than SOOO feet thick. Another effect of the persistent movement 

 from Eocene to Recent times was to push the hydrographic line 

 farther southwards in the Himalayan section, and farther east- 

 wards in the Baluchistan section. This process was assisted by 

 the great excess of silt brought down by the drainage of the 

 mountainous region on the north and west, over that contributed 

 by the drainage of the land on the peninsular side. This retreat 

 of the hydrographic line is especially marked in the large re-entrant 



1 Mem. Geol. Surv. Ind. vol. xlii (1917) pp. ^243] & [245]. 



