Vol. VI, No. 10.] The Rivers of the Delta. 545 



[NJB.] 



On this basis I venture to point out some of the 

 important changes which have occurred in the courses of the 

 Ganges and Brahmaputra since the date of Major Rennell's 

 survey, more especially in the Rajnagar area ; while pointing 

 out the sequence of changes due to the oscillation of the rivers, 

 I shall endeavour to point out their mutual connection 

 and to show that a synoptical view of the river action of the 

 last century and a half will show the connection of cause and 

 effect ; ^id the cause of the great changes will be found far 

 away to the north in the River Teesta. 



When Major Rennell surveyed the Delta, he found the 

 Brahmaputra flowing into the Meghna, north of Dacca, a 

 course which (there is evidence in the Ain-i-Akbari to show) 

 was the main channel of the Brahmaputra in the 16th century. 

 Within 50 years of this survey the main stream of the Brahma- 

 putra was flowing west of Dacca down the old Jenai River, 

 forming a junction with the Ganges near Jaffierganj ; the com- 

 bined streams deserted the old course of the Ganges between 

 Panchar and Nulluah of Rennell's maps and joined the Meghna 

 not far south of the big "pagoda" of Rajabari, about 45 

 miles in a straight line north of the junction of the Ganges 

 and Meghna as surveyed by Rennell, The course of the river, 

 roughly 120 miles long from near Nullua to Mehendiganj, was 

 forsaken in favour of a course from Nullua to Chiddypur 

 (Chandipur), approximately 20 miles in length, the direction 

 of the stream changing from S.S.E. to almost due E. There 

 is only one other change of importance to which I would call 

 attention at present, viz., the formation of an entirely new 

 river, the Nayabhangani, through the isthmus at Serampur in 

 Rennell's maps (latitude 23°), joining the Meghna with the old 

 course of the Ganges, a river which now forms part of the 

 main steamer route from Calcutta to Cachar and Assam via 

 Barisal. This stream, which at present has an average breadth 

 of over | a mile, worked its way through from the Meghna into 

 the old Padma, some years previously to 1800. Now these 

 great changes, which appear to be merely the arbitrary 

 workings of a young and violent river, are, I think, attribu- 

 table entirely to one cause, — a cause the importance of which 

 has been recognized, but the effects of which have never been 

 adequately observed. 



It has been admitted by more than one authority that the 

 change in the course of the Brahmaputra was due to the fact 

 that, owing to an abnormal flood in the year 1787, the River 

 Teesta changed its allegiance from the Ganges to the Brahma- 

 putra, which found a fresh outlet through the Jenai, the 

 present main stream of the Brahmaputra (or Jamuna, as it is 

 here called) This abnormal flood was felt far to the south 

 down the Meghna and the Ganges, and the evidence afforded 

 by old correspondence of the period, leads one to the inference 



