290 Mr Connevu’s Analysis of the 
Phosphate of Lime, with a little Fluoride of Calcium, A 50.94 
Carbonate of Lime, y ‘ . 4 ‘ 11.91 
Siliceous matter, ‘ i : ; : 33.10 } 
36.58 
Water, é és : : é P 3.48 Sm 
Potash and Soda, : ; : 3 AT 
Bituminous Matter, ’ : - : Z 12 
Phosphate of Magnesia, Trace 
Animal Matter, Trace 
100.02 
The most unexpected part of this analysis was the occurrence 
of so large a proportion of siliceous matter. Judging from the 
beautifully perfect appearance of these scales, presenting a lustre 
as fine in all likelihood as they possessed when they clothed the 
sides of the immense living tenants of the primeval waters, we are 
naturally led to expect no great change in their nature. A little 
reflection, however, will show us that as fish scales are known to 
contain a good deal of perishable animal matter, in addition to 
the more permanent animal earths, which enter into their com- 
position, it is necessary that the place of this destructible matter 
should be taken by something more durable, in order that the 
original form may be preserved. This seems to be the origin of 
the siliceous matter ; and, in proof of the justness of this view, it 
need only be mentioned, that when the scales are acted on by 
acids, the insoluble matter remains behind as a fine siliceous 
skeleton, formed, there can be little doubt, by the infiltration of 
dissolved siliceous matter which has gradually taken the place 
of the decaying animal matter. The fossil scales, on this view, 
ought to consist of the infiltrated matter, together with the ori- 
ginal animal earths ; and this is exactly what we find to be the 
case; and it so happens, that in the present instance we are 
enabled to determine, with some degree of plausibility, that even 
the relative proportions of the different constituents haye been 
to a considerable extent preserved. We luckily possess an ana- 
lysis of the scales of the recent Lepisosteus, as well as of several 
2 
> (jac ein, 
