230 Journal of the Asiatic Society of Bengal. | November, 1905. 
30. Some remarks on the Geology of the Gangetic Plain.—By 
EK. Motony. [With one plate. | 
It requires no argument to prove that the present gangetic 
plain is the alluvial deposit of the river Ganges, and that the 
whole of the area of the gangetic plain south of the Himalayas. 
must at one time have consisted of a network of morasses and 
river-channels very similar to the Sunderbans at the present time. 
It is also evident that, over the whole area of the United Pro- 
vinces of Agra and Oudh, so far from the Ganges being at pre- 
sent engaged in raising its flood plain, it has become an agent of 
denudation, and has, long since, entered on the work of denuding 
the whole of its plain which lies above flood-level. 
It may be taken as proved that this great change has been 
occasioned by the submergence of the area at the mouth of the 
river. 
The period at which this important movement took place 
must have been very remote. 
The river has eroded a bed in the old alluvium which is in 
many places several miles in width. 
Within the limits of the former bed there is a considerable 
amount of later alluvium, but it varies very much from the older 
alluvium in its characteristics, and, in most places, there is a very 
well-marked line of demarcation between them 
Most of the recent alluvium is liable to be flooded during 
high floods of the Ganges, though there is some which has never 
been flooded during the memory of man. This is probably due to 
deposit of sand and light soil by the action of the wind during 
the hot weather. 
In the recent alluvium the substratum is nearly always pure 
river sand, the finer soils being deposited in shallow water where 
the current is usually less. 
Another difference is that the recent alluvium never contains. 
nodular limestone (kwnkar), which occurs in most places in the 
old alluvial deposits. 
I have perhaps made this assertion more positive than the 
text-books would appear to warrant, but I have never come across 
an instance in which kunkar was found in soil that clearly 
belonged to the recent alluvium, though I have occasionally found 
it in a locality near the boundary of the new and old alluvium. 
The soil also differs, the recent alluvium being generally 
much more fertile, at any rate in the eastern portion of the United 
Provinces, where the recent alluvium contains a percentage of the 
black cotton soil brought down by the Jumna and its tributaries 
from Central India. 
The area that lies between the extreme limits up to which 
the Ganges has excavated its bed in the old alluvium may be 
styled the ‘ Khadir.” 
Having had good opportunities for observation in the Ghazipur 
