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ADDITIONAL NOTICES RELATIVE TO THE FRESH-WATER LIMESTONES 

 IN THE VICINITY OF EDINBURGH, BELONGING TO THE CARBONI- 

 FEROUS GROUP OF ROCKS. By Dr Hibbert. 



In a paper lately read before the Royal Society of Edinburgh, 

 Dr Hibbert explained the progress which had been made, since 

 he first pointed out the existence of plants as well as of fish and 

 saurian animals, in the fresh-water limestone of Burdiehouse, to- 

 wards a farther investigation of these animal remains. The inquiry 

 has been subsequently carried on by the Royal Society of Edinburgh, 

 through their General Secretary Mr Robison. 



The more important animal relics, which the limestone quarry of 

 Burdiehouse has yielded, are various kinds of fish, some of them refer- 

 rible to the extinct genus of the Palaeoniscum, large scales, evidently 

 saurian, exhibiting a most brilliant lustre, and presented in remark- 

 able abundance, the epiphyses of vertebrae, numerous fragments of 

 bones much broken, and teeth which, in their internal structure, give 

 incontestible evidence of the dentition that is peculiar to animals 

 more or less resembling the crocodile, or gavial.* 



The above figures represent the section of a tooth, obtained by Mr Robison, which 

 had been accidentally broken in a longitudinal direction. 

 a shews the root of the tooth. 

 b is the reverse side of the same, in which a small internal cavity may be observed, 



indicative of a newer replacing tooth in an incipient state of growth. 

 c is the larger fragment of the tooth in which the newer tooth, of a conoid form, 



(protruded from its alveolus) is contained. 

 The cavities of the new tooth, and of the intermediate space of the old tooth, are 

 at present filled with earthy substance. 



The author then proceeded to point out other localities in which 

 beds of fresh- water limestone crop out. 



• A wood-cut representation of the first saurian relic discovered in the 

 quarry by Dr Hibbert, consisting of a large tooth in a beautiful state of in- 

 tegrity, was given in the last number of the Journal. See the Author's let- 

 ter to Professor Jameson, page 193. 



