20i< Mv Connell on the Chemical Nature (>/' Fossil Scales. 



•of a still larger scale. It adhered to coal, and had a yellowisli 

 colour, and a good deal of lustre, but the surface was not ob- 

 served to be punctured. 



The chemical details of analysis need not be entered, into, as 

 the general process followed was the same as that formerly 

 given in the Edinburgh Transactions. 



The result was as follows : — 



Phosphate of lime, with a little fluoride of calcium, 55.75 ; carbonate of lime 

 15.80; siliceous matter, 10.17; alumina, 2.C2 ; phosphate of magnesia, 

 trace ; potash, and soda, partly as sulphates, 1.06; water and bituminous 

 matter, 6.46 = 98.12. 



If we suppose that about one-half of the animal matter in 

 the oi'iginal scale had been replaced, partly by siliceous and 

 partly by calcareous matter, its composition must have been 

 entirely analogous to that of the scales of the Lepisosteus and 

 Burdiehouse fish. 



The other fossil scale analyzed was a very beautiful one from 

 the Tilgate Forest, Sussex. Its form was quadrangular, without 

 those bifurcating processes which Mr Mantell has supposed to 

 be characteristic of fish-scales, and without any carinated appear- 

 ance. Size about three-fourths of "an inch square ; colour 

 black ; lustre considei'able ; punctures scarcely visible on its 

 surfitce, with a double lens ; thickness varying from one-fifth to 

 one-tenth of an inch. Matrix, a calcareous grit, nearly entirely 

 soluble in acids. This fossil had been considered as the scale 

 of a saurian animal, and I therefore undertook its analysis 

 with some degree of interest, for the purpose of ascertaining 

 how far this view of its origin would be borne out by its che- 

 mical nature. The result leaves, I imagine, little doubt that it 

 is to be considered as the scale of a fish. 



Its constituents were foimd to be, 



I Phosphate of lime, with a little fluoride of calcium, 60.13; carbonate of 

 lime, 27.94 ; siliceous matter, 3.42 ; alumina, .82; phosphate of magne- 

 sia, trace; potash and soda, partly as sulphates, 1.43; water, carbon, and 



:. sulphur, 6.71 ; = 100.45. 



The large proportion of phosphate of lime here indicated, 

 appears to be incompatible with the idea of this scale having 

 belonged to a saurian animal ; and there seems reason to be- 

 lieve that its original composition, as a fish scale, was analogous 

 to that of the others which have been examined. The replace- 



