yU GEOLOGICAL NOTES ON ASSAM. 



Jo not hesitate to maltreat them, even to the extent of decapitation. 

 In the hills on the south of the valley, the flankiug ridges of the 

 Patkai rang-e, these same sandstones are seen to have their usual capping 

 of coarse conglomerates. I obtained a fossil elephant^s toothy found by 

 Bryan Comber,, Esq., in the gorge of the Deijmoo, north of Dibroogurh. 

 Tliese true Sub- Himalayan rocks extend for a considerable distance west 

 of Tezpoor. They are easily recognized from the Bramahpootra forming 

 a distinct flanking range to the higher mountains beyond ; the white 

 cliffs produced by the frequent slips on the south side of the wedge-like 

 ridges betray these rocks from a distance. It would be very interesting 

 indeed to ascertain whether the fact noijgd by Captain Godwin Austen 

 is due to the removal of these rocks in that position by denudation, 

 whether total or partial, a remnant being still left, though perhaps 

 concealed by recent detritus ; or whether it can be that they never 

 existed there. This latter supposition receives considerable encourage- 

 ment from the fact, already noticed, of the extension of low hills of 

 gneiss from the Shillong table-land far to the north of Goalparra, towards 

 the Himalaya. Indeed the significance of this latter fact cannot be 

 nullified by the settlement of the question of a break in the Sub- 

 Himalayan chain, apparent or real. The connection or relation of the 

 crystalline rocks of Assam to those of the Himalaj^a would not be set 

 aside by a thin intervening band of such sub-superficial rocks as these 

 tertiary sandstones; and it promises to form a telling point in the 

 discussion of mountain formation. The relation of the Shillong table- 

 land to the Himalayan mass may not after all be imaginary ; but it 

 mnst be something very different from what is usually implied by the 

 expression ^'mountain system .^■' With independent reference to the 

 question of disturbance, the very marked contrast in the behaviour of the 

 same rocks to the Himalayan mass and to the table-land mass, is worthy 

 of attention. In whatever degree the observation by Captain Godwin 

 Austen comes to be confirmed, it is unique — from the Bramah Khoond 

 436 ) 



