XVIL — On the Geology of the Banks of the Ganges , from Calcutta 
to Cawnpore . 
By JOHN ADAM, M.D. 
[Read Feb. 19, 1819.] 
There is no rock on the banks of the Hoogly, nor do we meet 
with any after entering on the main stream of the Ganges, until we 
approach the province of Bahar. The soil, in general, seems to 
consist of a mixture of argillaceous earth and sand, in such propor- 
tions as to make a soft attenuated compound, excellently adapted 
for the purposes of vegetation, and conducing, in a great degree, to 
that fertility for which the plains of Bengal are so celebrated. The 
only peculiarity in these ingredients of the soil is the great abund- 
ance of mica, which, mingled in minute grains, often gives a 
brilliant shining appearance to an extensive plain of sand, and is 
found to prevail, more or less, on the banks in the whole course of 
the river. Strata of sand, of various colours, are frequently lying 
over each other, which seem to have been formed in successive 
seasons ; and above these, mixed soil or sand approaching to it, 
with a surface destitute of herbage, or bearing a coarse grass or reeds, 
in detached parcels. 
After leaving the low lands of Bengal, the Rajemalial chain of 
hills presents itself, and diversifies the prospect and character of the 
country. Here, for the first time, we discover rock ; and from this 
point commences the series of specimens which is the subject of the 
