Organic Remains of Burdiehouse. 291 



other recent fishes, by Chevreul ; 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. Agassiz, 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. 

 Chevreul's analyses are as follows :* 





Lepisosteus. 



Perca labrax. 



A Chcetodon 



Phosphate of Lime, 



46.20 



37.80 



42 



Carbonate of Lime, 



10.00 



3.06 



3.68 



Gelatinous Animal Matter, . 



41.10 



55. 



51.42 



Phosphate of Magnesia, 



2.2 



.90 



.90 



Fatty Matter, 



0.10 



.40 



1. 



Carbonate of Soda, 



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 2 1 2° ; 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 2| 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 



* Berzelius, Lehrb. iv. 628, 



oo2 



