:l8 PEOCEEDINQS or THE 



the country. This is very marked in the northern half of the 

 Soondreebun which passes insensibly into the rice-swamp of 

 Bengal : here a village stands, like Calcutta, along the river-bank, 

 just out of the water, enveloped in trees ; before you get a mile 

 from the river you reach the rice-swamp ; after you have crossed 

 this, for two or three miles you see another large clump of trees 

 before you ; and in this you find a village standing on the bank 

 of another stream ; and so on ad infinitum. Near the sea, how- 

 ever, in the Soondreebun, the banks of the creeks, and indeed the 

 whole land, as seen from a boat two or three miles off, look to me 

 (in some conditions of the atmosphere) lower than the sea. They 

 are really only 2 or 3 feet above high-water mark : on the night 

 of 31 Oct. 1876, a storm-wave passed, 10 feet high, over the 

 islands in the mouth of the Megna, and also swept both its banks ; 

 98,000 people were drowned. 



In putting forward this view of the physical geography of a 

 river-delta, I am aware that it has been strongly contested. 

 Thus Mr. Eainey, in the paper I have already cited, says : — " In 

 non-deltaic lands the water radiates from an elevated central 

 point and flows outward ; and this may be termed the centrifugal 

 system of drainage. But in deltaic land, as the Soondreebun, 

 the water from the surrounding parts flows inward to a de- 

 pressed central point ; this may be termed the centripetal system 

 of drainage." Mr. Eainey also says that "the various streams 

 in the delta deposit the silt and sand they hold in suspension on 

 their own beds, which gradually rise above the level of the 

 adjacent lands." You will thus see that Mr. Eainey's views are 

 diametrically opposed to the account I have put forward. This 

 is an old controversy ; it arose from a statement of Liebig, who 

 said that the rice-fields of Bengal were annually fertilized by 

 silt, and thus enabled, without manure, to grow rice for a 

 thousand years successively unexhausted. On the exclusively 

 chemical theory Liebig was obliged to explain the perennial 

 fertility of the Bengal rice-fields ; and this was the way be did it. 

 But Eoxburgh pointed out that the valuable rice-lands, i. e. those 

 which grow dibbled rice, are outside the delta, and that they only 

 get rain-water which runs off them into the rivers. Against this, 

 persons, imagining they were propping up Liebig, were found 

 who advanced the decisive rebutter that the water from the 

 rivers does, outside the deltaic area, overflow the fields of dibbled 

 rice. Having thus brought this hotly contested matter to a pure 

 matter of i'act, I leave it, reiterating merely that I am entirely 

 of the opinion of Eoxburgh. It will be within the opportunities 

 of any Eellow of this Society to test the theory of the centri- 

 lugal system of drainage of rivers in their non-deltaic catchment 

 areas, as in that of the Thames valley. 



The Soondreebun is by no means of one uniform character. There 

 are (A) large areas of mud over which the tide flows gently at 

 high v\ater. Here, when the tide retreats, the mud hardens in 



