500 On the Fossil Bones of the Jamna River. [Sept. 



are to be met with in the Jamna, owe their existence to some pecu- 

 liar quality of the water alone ; and I do not consider the fossils of 

 the Jamna as at all connected with the natural kankar formation, 

 although at any depth that the artificial or deposit kankar formation 

 is found, they may reasonably be looked for. 



IV. — Note on the preceding. By James Prinsep, Secretary, fyc. 



More than a year has elapsed since Mr. Dean presented us with 

 a first selection from the fossil bones he had discovered while engaged 

 in blasting the rocks and impediments to navigation in the Jamna, 

 under Major Irvine, and afterwards Captain Smith, of the Engineers : 

 a few months prior to that, in November, 1833, we had been made 

 acquainted with the fact of their occurrence by Captain Smith, to 

 whose valuable sketches on the stratification of the Dual) alluvium 

 and notes on the position of the fossils, published in the Journal 

 for December, 1833, I ventured to add a few remarks, suggesting 

 the probability of their being subjacent to the kankar, and therefore 

 of an age anterior to the deposition of the great bed of alluvium of 

 the Sub-Himalayan plains, when all this part of the present continent 

 was still buried under the expanse of waters. 



This opinion has been combated by Serjeant Dean in the preceding 

 note, as well as in his memoir on the Duab strata, printed in page 

 273 of the present volume. 



The evidence of an eye-witness must be deemed sufficient, and the 

 theory of original deposit with the alluvium must be given up. Still 

 the hypothesis advanced in its stead by Mr. Dean, of the fossilizing 

 powers of the Jamna, and the probability of all the present specimens 

 having been mineralized in situ, does not appear adequate to meet 

 the difficulties of the case. 



It is so far true, that the bones are found in various stages of 

 transformation ; some in a crumbling state, the interstices filled with 

 the sand and kankar conglomerate of the river ; some lined, in the 

 cells of the bones, with calcareous spar, and chalky earth ; while 

 others are, as it may be termed, wholly fossilized, of a dark shining 

 brown colour, ponderous, brittle, of a conchoidal fracture, and retain- 

 ing little even of the bone-earth itself in their composition. The 

 substance into which the bones are thus converted, is a hydrated 

 oxide of iron. The animal matter of the bone is probably first re- 

 placed by it, and then the softer portions. The hard enamel of 

 the teeth resists decomposition for a long time, and its whiteness, 

 contrasting with the dark brown of the cavities and encasing jaw 



