Mr Connell on the Chemical Nature of Fossil Scales. 303 



which had existed in those scales while the animal was alive ; 

 as was shewn by the circumstance, that when the fossil scales 

 were acted on by acids, the siliceous matter remained undissolved 

 in the form of a fine siliceous skeleton. In order to connect 

 these analyses with those which are to follow, I again subjoin 

 the results. In the scales of the recent Lepisosteus, Chevreul 

 found 



Phosphate of lime, 46.20; carbonate of lime, 10.; gelatinous animal mat- 

 ter, 41.10; phosphate of magnesia, 2.2; fatty matter, 0.10; carbonate 

 of soda, 0.10 ; = 100. 



Those of the Megalichthys of Burdiehouse I found to con- 

 tain, 



Phosphate of lime, with a little fluoride of calcium, 50.94 ; carbonate of 

 lime, 11.91; hydrated siliceous matter, 36.58; potash and soda, .47; 

 bituminous matter, .12; phosphate of magnesia, trace; animal matter, 

 trace: = 100.12. 



And these results suggested the following comparison: — 



Scales Scales 

 Lepisosteus Megalichthys. 



Phosphate of lime, - - 46.20 50.94 



Carbonate of Lime, - - 10. 11.91 



Animal matter replaced in the Megalich- 1 ^ ^ 



thys, by hydrated siliceous matter, j 



97-3 99.43 

 Little doubt could therefore remain as to the true nature of 



the fossil scales of Burdiehouse. 



I am indebted to Lord Greenock for specimens of fossil 



scales from two other localities, of which I now propose to state 



the analysis. 



The first of these are the fossil scales found by his Lordship 

 imbedded in the coal of Craighall, near Edinburgh. These 

 have been considered to belong to the same fish as those of 

 Burdiehouse, and the chemical analysis fully supports this 

 view, the principal difference being that replacement of the 

 animal matter has not occurred to so large an extent as in the 

 Burdiehouse scales, a fact for which we might have been pre- 

 pared by the circumstance, that their lustre and general state 

 of preservation is not quite so fine as in the latter instance, 

 although still wonderfully perfect. 



The portion of the Craighall scale analyzed, was nearly 1 inch 

 long by half an inch broad, and was evidently only a fragment 



x 2 



