1863.] FEKGUSSON DELTA OF THE GANGES. 333 



now marks that of the western portion, and which is due — as will 

 be afterwards explained — to the joint action of the tidal and fluvia- 

 tile forces which meet at that point. 



4. Change in the Bed of the Brahmapootra. — It would have been 

 extremely instructive if the progress of the struggle between the 

 Megna and the Brahmapootra had been carefully watched and re- 

 corded; all we now know is, that when Major Rennell surveyed 

 these rivers in 1785, neither he nor any of his assistants had any 

 idea that the Brahmapootra had not always flowed, and would not 

 always continue to do so, in the channel in which he then found it. 

 We now know that, though a considerable body of water may flow 

 that way in the rains, yet during nine months in the year a creek, 

 or rather chain of ponds, 100 or 200 feet wide, and everywhere 

 fordable, represents the river that a little more than half a century 

 before flowed through that country in seven-mile reaches, and with 

 a breadth of more than a mile and a half even in the dry season. 



It is unfortunate that Buchanan Hamilton* did not visit this 

 country when surveying the neighbouring districts in 1807-10, as 

 the change must then have set in ; and his greater knowledge of the 

 language and of the customs of the natives would have led him to 

 remark upon the anomaly of the smaller stream (the Megna) giving 

 its name to the Brahmapootra, from their junction at Sonerampore 

 to the sea, proving that the bed belonged to the smaller river, and 

 that it had been invaded by the larger ; and proving also — for this 

 class of evidence is very cogent in these regions — that the invasion 

 had taken place after the country had been sufficiently inhabited 

 and settled to have the names of its rivers fixed on the bases they 

 now maintain. So far as we can judge from appearances, this could 

 hardly have occurred very long ago. 



AVhen the survey now in progress is completed, it will not be 

 very difficult to estimate this epoch approximately. The first thing 

 to be ascertained is, of course, the quantity of silt brought down by 

 the Brahmapootra ; then to estimate the area of the Syihet Jheels 

 filled up by the great delta formed in them by the waters of the 

 Brahmapootra, checking this with the area of the delta at the 

 mouth of the Megna, which remains to be filled in ; and, with a few 

 borings, all this ought not to be very difficult. In the meantime, it 

 certainly is to be regretted, in an economic point of view, that the 

 combined Syihet rivers prevailed in this struggle. They cannot fill up 

 their own swamps, because they possess no silt ; and they shut out 

 the only river that is capable of doing it for them. Now, however, 

 every year must make their condition worse; for, as the delta extends, 

 the land between them and the sea, below Dacca, must rise, and they 

 consequently must deepen, and their water spread, until the whole pro- 

 vince may become a submerged peat-factory, from which fate nothing 

 can save it but inviting back the river they have just expelled. 



5. Opening of the R. Jennai.— The first river the Brahmapootra met 

 which could afford it a means of escape was, as just mentioned, the 



* His surveys, in a mutilated form, were published in 3 vols. 8vo, by Mont- 

 gomery Martin, in 1838. 



