478 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. [May 16, 



portion of a rib, states as follows : — ' The bone was subjected for two 

 days to the action of dilute muriatic acid ; and when examined at 

 the end of this period, it had become as flexible as a recent bone 

 submitted to the action of the same solvent. The cartilage and 

 gelatine had not been perceptibly altered by time.' It is long since 

 the observation was made by many other persons, and especially by 

 Schmerling (Eecherches sur les ossements cles cavernes de la pro- 

 vince de Liege, 4to. 1833, lere par. pp. 18-52) \ and the remarkable 

 researches on this subject recently made by M. Delesse, and which 

 he is about to publish, have demonstrated that the organic change 

 in bones by no means bears a relation to their palseontological an- 

 tiquity. For example, he has found that the teeth of the bone-bed 

 in the Upper Keuper at Oberbronn contain more azotized organic 

 matter than most of the tusks of the Mastodon and Elephant found 

 in tertiary or diluvial deposits. The amount of azote which they 

 yield is even almost double that in the tusks of the Mastodon in the 

 Miocene limestone of Sansan or in the Miocene deposits of the Upper 

 Garonne. Thus it is evident that, if the amount of organic matter 

 generally diminishes in proportion as the age increases, there are, 

 nevertheless, exceptions to that general rule. 



" As to external appearance, that depends also on the circum- 

 stances of the locality. It is not long since a large number of bones 

 of the Hymia spelcea were sent 10 me, which had been obtained from 

 an ancient alluvial deposit in the centre of France. They were in no 

 degree changed in weight or colour, and in external appearance they 

 were quite as fresh, if not more so than the fragment given to you 

 by M. Delesse. I have some of them now in my possession ; and 

 they are still so much impregnated with animal matter, that I was 

 able with the utmost ease to saw and cut them with a flint knife. 

 On the other hand, I have now before me a statuette made of stag's 

 horn, obtained from a grave at the external base of a barrow, cer- 

 tainly not older than the 12th century, the substance of which is so 

 much altered that it might be said to be fossilized, in a certain sense 

 of the term, as much as the greater part of those found in caverns or 

 diluvium. Hence we perceive that the greater or less amount of 

 alteration in bones is not a character from which we can absolutely 

 determine their palseontological antiquity. 



" "With regard to the mode by which the fossil bones of M. Delesse 

 have been sawn, I must confess that at first sight I thought, as M. 

 Desnoyers did, that the operation must have been performed with a 

 metallic plate ; but upon a more attentive examination of recent bones, 

 I became convinced that the peculiar appearance presented by the 

 section of one of the bones in the possession of M. Delesse must have 

 been produced by the employment of a sharp tool of flint, rather than 

 by a metallic plate, which has always given me a section with a very 

 different surface. I send you the extremity of a tooth of Hycena 

 spelcea, which has been sawn by a flint. If you examine with a 

 magnifying glass the plane of the section, you will find the same 

 system of strice as are observed in the bones collected by M. Delesse, 



