210 Dr Hissert on the Limestone of Burdiehouse, 
burgh, has had his views directed to this subject, as, indeed, to 
other comparative inquiries of the same nature, relative to the 
change which animal remains of so early a geological date as 
those of Burdiehouse have experienced. His valuable memoir 
on this subject will appear in the present volume of the Transac- 
tions of the Royal Society of Edinburgh. 
I have been favoured by Mr Connex with the result of 
his examination of the scales of the Megalichthys, which he has 
subsequently compared with an analysis given by Curvrevt of 
the scales of the recent Lepidosteus. These two results, with 
the view of comparison, I have arranged in a tabular form. 
M. CuHEvrEvuL’s ANALYSIS OF THE SCALES OF ANALYSIS OF THE SCALES OF THE FossIL 
THE RECENT LEPIDOSTEUS. Mecaticutays, sy A. ConnELL, Eso. 
Phosphate of Lime, with a little 
Phosphate of Lime, ) ok. 94620 Fluoride of Calcium, . . 50.94 
Carbonate of Lime,. . . . 10. Carbonate of Lime, . . . . 11.91 
Phosphate of Magnesia, . . 2.02 Phosphate of Magnesia, trace 
Carbonate of Soda, . . . . 10 Potash and ‘Soda, -."- =. fe AZ 
Gelatinous Animal Matter, . 41.10 Animal Matter, trace 
Fatty Matter,. . . . . .- 40 
Siliceous Matter, . . 33.10 
WA RECT son cuca asice Secure 
— 36.58 
Bituminous Matter,. . . . 12 
99.82 100.02 
Upon the assumption that the scales of the recent Lepidos- 
teus and those of the Megalichthys identify themselves with each 
other, as far as external character and consistence are concerned, 
the foregoing Table of chemical comparison is a most important 
and instructive one. 
With regard to the earthy ingredients of the phosphate of 
lime and carbonate of lime, it will be seen at first view, that, in 
both the fossil and recent animals, they constitute about three- 
fifths of the solid matter of the scales. In the fossil animal, they 
have remained in a proportion, most probably, unalterable. 
