656 DR JAMES STARK ON THE EXISTENCE OF AN OSSEOUS STRUCTURE, &c. 



to ascertain whether the vertebrae of cartilaginous fishes were known to occur in 

 a fossil state, whether they had themselves seen any, or, if recognised, what 

 they were taken for. In answer, it was stated, that the vertebrae of cartilaginous 

 fishes were unknown in a fossil state, nor were they ever expected to be met 

 with on account of the destructible nature of the cartilaginous matter of which 

 they were supposed to be alone composed. Dr HIBBEBT WARE added, that M. 

 AGASSIZ had several times expressed to him the same sentiment. Both Dr 

 HIBBERT WARE and Mr TREVELYAN, however, think they have seen in the chalk, 

 and in the new tertiary strata, bodies like what I have shewn constitute the 

 essential portion of the spinal column of cartilaginous fishes. This, along with 

 the circumstance of the exact figures of the osseous portions of the vertebra 

 being preserved in the impressions of the cartilaginous fishes figured by M. 

 AGASSIZ, shews that, when the attention of geologists is drawn to the subject, 

 they will probably meet with them in the same strata as those in which the teeth 

 and spines occur. 



Specimens of the structures above described were laid on the table. 



21 HERIOT Row. 



