158 



Note on a tank Section at Sealdah. 

 Kulnah, Jessore. 



18 ft. 



25 ft. 



39 ft. 



[No. 2, 



3 ft. Sand. 



I ! q. nj, n ( Argillaceous sand passing into 

 \ stiff blue clay with shells. 



1 ft. 7 ins. Peat with tree stumps. 

 6 ins. stiff blue clay. 



2 ins. Peat. 4 ins. clay. 10 ins. Peat. 

 5 ft. 3 ins. Stiff grey clay. 

 Lowest tree met with. 



14 ft. 3 ins. Sandy clay. 



Sand. 



The depression was I think very extensive, if unequal ; thus I am 

 informed by Mr. Leonard that the peat bed occurs at a depth of 20 

 feet at Canning town on the Mutlah, the actual land level of which 

 place is certainly several feet below that of Sealdah, and a section of 

 a tank near Khulnah in Jessore, for which I am indebted to the 

 kindness of Col. Grastrell, shews a peat bed at a depth of 16 ft. 6 ins. 

 to 20 feet, and trunks of trees with roots attached at various levels 

 from 18 to 24 feet. This very interesting section is shewn in the 

 accompanying wood cut, Fig. 2. 



From these facts, I infer an average depression of the Gangetic 

 delta of 18 or 20 feet since the land surface existed, which is marked 

 by the Sundri trees in situ. It is noteworthy that the trees, in all 

 the sections I am acquainted with, are restricted to a vertical thickness 

 of from 8 to 10 feet, and that the strata above, though frequently 

 full of fragmentary plant remains and sometimes fresh water shells? 

 shew no indications of former land surfaces. This indicates not only 

 the uniformity of the depression, but also that it was everywhere more 

 rapid than would be compensated for by the deposition of sediment. 



