On the Structure of the Delta of the Ganges. 339 



larger mammalia, the remains perfectly fossilised, and exist- 

 ing in abundance in the superior strata of sandstone. The 

 general inclination of all these strata varies from twenty to 

 thirty-five to the horizon." It is most interesting thus to 

 find a succession of strata at the base of the Himalaya so per- 

 fectly identical with that extending from about 450 to 480 

 feet below the surface of lower Bengal. The singular oc- 

 currence of thin beds of blue marl with shells, in both in- 

 stances overlaying coarse conglomerate intermixed with lig- 

 nite, and underlaying beds of sandstone, links the two classes 

 of deposits in a remarkable manner, and would almost lead 

 us to believe that they owe their origin to the same mighty 

 ocean which reached to the foot of the mountains, and that by 

 movements of elevation in one locality, or of depression in the 

 other, their present difference of position was subsequently 

 attained. The similarity of the distribution of the fossils in 

 both instances will also be remarked, the mammalia chiefly 

 abounding in the upper deposits, Chelonians and Saurians in 

 the lower, while the mineralising material, hydrate of iron, is 

 alike in all. The fossils of the Jumna, of the valley of the 

 Nerbudda, of the Sub-Himalayan range, of the Irawaddi, 

 have been identified with each other, and it appears probable 

 that to this series may also be added the fossils of the Del- 

 ta.* The conglomerate forming the matrix of the Ava re- 

 mains, induced Dr. Buckland to assign them to diluvial for- 

 mations more modern than either the recent marine sedi- 

 ments of the tertiary formations, or the antidiluvian fresh- 

 water deposits, and to the same epoch the other members of 

 the above mentioned series most probably belong. 



In conclusion, it only remains for me to express my grate- 

 ful acknowledgments to Colonel D. McLeod, Chief Engi- 

 neer, for the ready access he has granted me to all official 

 papers or plans connected with the boring operations, from 



* Vide Note E. 



2y 



