Organic Remains of Burdiehouse. 291 
other recent fishes, by Curvreut ; and, it is very interesting that, 
on comparing the analysis of the scales of the Megalichthys of 
Burdiehouse with those of the Lepisosteus, to which, on the high 
authority of M. Acass1z, the Megalichthys is in other respects 
allied, we find a considerable approximation between the propor- 
tions of the different constituents of the scales of the recent and 
of the fossil fish on substituting siliceous matter for destructible 
animal matter ;—not certainly a numerical identity, but still a 
marked analogy, and one of a much stronger description than be- 
tween the fossil scales and those of the other recent fishes. 
CuHEVREUL’s analyses are as follows :* 
Lepisosteus. Perea labrax. A Choetodon. 
Phosphate of Lime, i ; 46.20 37.80 42 
Carbonate of Lime, : : 10.60 3.06 3.68 
Gelatinous Animal Matter, . s 41.10 55. 51.42 
Phosphate of Magnesia 4 ‘5 2.2 .90 .90 
Fatty Matter, 3 ; : 0.10 40 i 
Carbonate of Soda, .- é f 0.10 .90 1. 
100. 98.06 100 
On comparing the proportion of the first three of the above 
constituents with the corresponding ingredients in the fossil 
scales, we shall see the analogy, and it is somewhat increased by 
the circumstance, that the water was in combination with the si- 
liceous matter, as I ascertained by igniting a portion of it after 
drying it at 212° ; so that in reality both these constituents, form- 
ing together a hydrated siliceous matter, have been substituted 
by infiltration for the animal matter. 
We may recall to remembrance, that the limestone matrix 
contains about 22 per cent. of earthy matter, so that we can be 
at no loss to account for the occurrence of the siliceous matter. 
The following comparison, framed on this view, will show the 
* Berzextus, Lehrb. iv. 628, 
002 
