272 On the Strata of the Dudb Alluvium, [May, 



the animal has either died in, or has been after death washed, to, the 

 position it now occupies, on which the deposition of kankar and other 

 substances has still continued, thus rapidly enveloping it in a crust, 

 which accounts for the absence of petrifaction, (specs, a and b ■) for I 

 have observed that in very few instances, where organic remains have 

 been imbedded in the kankar deposit, has the bone materially differed 

 from the present specimen. Instances have occurred, and still may be 

 referred to, as existing at the present moment, whereon the deposit 

 having attained the highest level of the river, or from the sinking of 

 the river in its bed, it has been left at a level scarcely ever attained 

 now at its highest rise ; where the formation has necessarily ceased in 

 these cases, those bones which with other extraneous substances help 

 to form the upper crust or surface of the deposit, are generally from 

 their being larger than the nodules of the kankar, but partially imbed- 

 ded ; that part which has been exposed to the action of the water, is 

 perfectly petrified, and is rather darker than the surrounding kankar : 

 whereas the part below the surface maintains the same colour, ap- 

 pearance, and quality, (fossilized, but not petrified,) as this specimen or 

 nearly so, allowing for the difference in the size of each, (spec. 7,) 

 and the proximity of the petrifying medium to the former, which, I 

 consider ample proof of the rapidity of the formation ; as, if the process 

 was slow, many instances must occur of bones or wood in a thorough- 

 ly petrified state, being met with imbedded in these masses. I have 

 found, however, nothing approaching nearer a state of petrifaction 

 than specimen Nos. 7, which are completely fossilized, but not 

 petrified. 



Another proof of the rapidity of the formation is, that the interior 

 is not much more consolidated than the interior of a bed of loose no- 

 dule kankar, and the only difference between them is, that the inter- 

 stices between nodules in the latter are generally filled with loamy 

 clay, whilst here sand occupies its place. 



The antiquity of this particular specimen must be very considerable, 

 as I question if the upper parts are covered during the highest levels. 

 The river has deepened its bed abreast of it about 25 feet, which even 

 supposing it to have never occupied a higher level than at present, 

 which cannot of course be now ascertained, precludes the possibility 

 of any addition having been made to it for ages. 



Numerous instances of organic remains occur in other masses of 

 different deposits lying in all directions round it, but the grand scale 

 both of these remains and of the mass in which they are imbedded, 

 completely throws them into the shade. 



