in the Neighbourhood of Edinburgh. 2'2l 



The two different characters of mineralization are exhibited in the following 

 Table. 



Fossil Scales of the Megalichthys contain Thorny Rays of the Gyracanthus contain 



Carbonate of Lime, . . 11.91 Carbonate of Lime, . . 33.86 



Hydrated Siliceous Matter, 36.58 Siliceous Matter, . , 10.22 



48.49 44.80 



These observations have been suggested by the important analysis of Mr Con- 

 nell. But he is far better qualified than myself to enter into questions relative to 

 the chemistry of geology. 



I shall, lastly, make some few remarks upon these large rays, as they are found in 

 other localities,. 



It would appear that the large bony rays of the Gyracanthus are not confined to 

 the limestone of Burdiehouse, as I have seen specimens of them collected from the 

 argillaceous shale of Fifeshire. Similar relics have also been discovered in Northum- 

 berland. 



In the next place, large bony rays, referable to other placoidian fish, appear in 

 the shale of the coal-fields of Glasgow ; they are likewise found in limestones of ma- 

 rine origin, as in the mountain-limestone of Ashford, from which locality I procured 

 them during the course of the last summer. Dr Simpson of Bathgate found a sili- 

 cefied organic substance in a mountain-limestone of marine origin, which, if it had 

 not been in so old a deposit, I should have taken for a belemnite. It was obtained 

 from Kate Shield's or Crawford's quarry, near Bathgate. M. Agassiz thinks that it 

 indicate an interior cavity (from which the organic matter must have been removed) 

 of one of these large rays. 



SECTION XV— THE COPROLITES OF THE LIMESTONE OE BURDIEHOUSE. 



From the numerous relics of small and immense finny ani- 

 mals discovered in the quarry, it cannot surprise us to find that 

 fcecal remains should occur in an abundance, rivalling perhaps in 

 this respect the particular locality which very early excited the 

 attention of Dr Buckland, and to which he has given the name 

 of the Cloaca maxima of Gloucestershire. 



In inspecting the very exact figures of the coprolites which 

 have been published in the excellent memoirs of Dr Buckland on 

 this subject, it might be expected that we should find these 

 shapes abundantly developed in the limestone of Burdiehouse ; 

 but the contrary is the fact. The peculiar forms of the fcecal 

 contents of the intestinal canal must, from their aqueous submer- 



