300 Mr Connell on the Chemical Nature of Fossil Scales. 



tions in llie specific characters which have hitherto prevented 

 their being determinately ascertained. Of the more limited ge- 

 nus Helops, every where rare in Scotland, the species become 

 very scarce in the north. Only two specimens of Helops cara- 

 bo'ulcs were taken in Sutherland, by Mr Selby. Of the Chry- 

 somel'idcB very few fell under our observation ; and it may be 

 noted as a singular feature in the entomology of this north-west 

 district of Scotland, that not a single species of the genus Cocci- 

 7U'Ua, usually so frequent in other parts of the country, was ob- 

 served. The only insects of the genus captured during the ex- 

 cursion were three specimens of Coccinella tredecim punctata, 

 which were taken by Dr Grevillc, not in Sutherland, but in 

 the adjoining county of Cromarty, between Invergoi'don and 

 Tain. 



On the Chemical Nature of Fossil Scales^ as illustrative of the 

 Character of the Animals to which they have belonged. By 

 A. CoKNELL, Esq. F. R. S. E. &c.* Communicated by the 

 Author. 



The difficulty which has often been experienced in determin- 

 ing merely from external characters, whether fossil scales be- 

 longed to a saurian animal or a fish, and the importance of this 

 question, sometimes as characterising the geological formation, 

 and at others as fixing the epoch of the fossil animal, render 

 the inquiry of some interest, whether chemistry can lend its aid 

 in solving the problem. 



It was, I believe, Mr Hatchet, who first drew a distinction, 

 in point of chemical nature, between the scales of recent reptiles 

 and those of recent fishes. He ascertained that the scales of 

 serpents, lizards, and such like animals, consist chiefly of a hor- 

 ny substance, of the nature of coagulated albumen ; whilst those 

 of fishes he found to contain a considerable proportion of phos- 

 phate of lime, and to be of the nature of bone -f-. Such expe- 



• Read to the Chemical Section of the British Association, at Dublin, 12th 

 August 1835. 



f Phil. Trans. 1800, p. 373-4. 



