GENERAL CONSIDERATIONS. 1 19 



same time in a certain measure limits of deposition for the formation 

 immediately south of each. 



Mr. Medlicott very early came to the conclusion that the nummu- 

 Northem limit of the Ktic boundary, the main boundary, and the Na 

 Siwalik conglomerate. han-Siwalik boundary were practically limits of 

 deposition ; and his reasons are so clear and decisive as to be convinc- 

 ing. Taking the youngest member of the Tertiary zone first, 

 namely, the Siwalik conglomerate, no man having once looked at its 

 geographical position would for a moment entertain the idea that it 

 had ever extended in an unbroken sheet far away into the region of 

 the Outer Himalaya. As early as the first quarter of this century Dr. 

 Hugh Falconer, whilst collecting the vertebrate remains from the 

 Sub-Himalayan hills, remarked on the similarity between the Siwalik 

 conglomerate and the present deposits of the large rivers. He says *, 

 " If the beds of the Jumna and Ganges were to be upheaved in the 

 " same way as those of former rivers, the appearance of the strata 

 <l would be exactly similar." Mr. Medlicott, carrying out the same 

 idea, found in the course of mapping the area north-west of the 

 Ganges that the Siwalik deposits varied according to their position 

 with regard to the great rivers. He remarks 2 "in the range between 

 11 the Ganges and Jumna clays are very subordinate, and the conglo- 

 " merates are composed of the harder quartzite pebbles, just like the 

 " shingle now found in the great mountain torrents. This portion of 

 "the range is in fact an ancient diluvial fan of the rivers Tons, Jumna, 

 " and Ganges." A similar generalization holds in the country taken up 

 by the present memoir. Between the Ganges and Rimganga, a short 

 distance from the plains, there rises an elevated schistose area, crown- 

 ed by a mass of gneissose granite forming the summit of Kalogirhi 

 (Kaland^nda), and without any important rivers draining south. Now, 

 it is here that there is a corresponding absence of the U. Siwalik 

 zone. The eastern termination of the Cha*ndi hills represents the 

 eastern limit of the deposits of the direct parent of the Ganges and 



1 Palaeontological Memoirs, Vol. 1, p. 33. 

 3 Manual of Geol. of India, p. 541. 



( '77 ) 



