1835.] and Site of Fossil Bones in the Jumna. 263 



situation as peculiarly corroborative of my remarks relating both to 

 these banks and to the kankar formation. No instance, however, has 

 ever been known of petrified or fossil animal, or vegetable remains, 

 having been found fairly imbedded in or under this stratum. 



Another formation of these hanks is occasioned by the current sap- 

 ping the high and abrupt banks of the river, by washing out the stra- 

 ta of compact sand, when such large masses of stiff clay are detached 

 and thrown into the channel, as to defy the efforts of the stream to 

 dislodge them, which if not speedily effected, a sufficient time has only 

 to elapse to clear the outer parts of the earthy matter which may have 

 fallen with them, which together with sand immediately deposits it- 

 self in rear, when every hour secures and strengthens them in their 

 position against the stream, (fig. 3. PI. XIV.) The interstices (should 

 there be any) are soon filled up with any extraneous substances that 

 may be lodged by the current. Those organic remains which may 

 happen to be imbedded, or rather buried under this sudden deposit, 

 if petrified in that situation, may be easily distinguished, as they inva- 

 riably adopt in the process of petrifaction, the hue of the mass with 

 which they are in contact, and which, when the process is complete, 

 nothing will remove, and the porous parts of the bones either re- 

 main empty, or are filled with carbonate of lime, infiltrated, whilst 

 in solution. The same remark applies to wood or any other substance. 

 In every other situation the interstices of the fossil to which the water 

 has unrestrained access, is filled with either silicious or argillaceous 

 matter, and frequently with a composition formed of both. For the 

 proper consolidation of either of which, however, the presence of the 

 carbonate of lime is necessary. 



Both these formations may be, and frequently are, instanced in one 

 specimen, where from fracture or decomposition, sand or clay may be 

 admitted to one part, when the composition is formed, whilst it is ex- 

 cluded from those more perfect, the pores of which will be either filled 

 with crystallized carbonate, or remain empty as above stated. 



By the continual cutting away, and falling in of the banks of the 

 river, the accumulation of alluvial matter in some places is neces- 

 sarily very extensive. The strength of the current preventing its 

 deposit in the channel, it is carried down to the bend of the river, 

 next below whence it has been dislodged, in the shape of thick sedi- 

 ment, and deposited there ; the sand which accompanied its removal is 

 from its greater specific gravity deposited in the bed of the channel. 

 This alluvium forms in banks from 6 to 14 feet thick, and composes, 

 on a rough calculation, not less than 80 or 100,000 acres of arable 

 land, of the first quality, between Agra and Allahabad ; producing by 



