294 Mr Connetu’s Analysis of the 
able cireumstances,—we shall obtain a substance almost identical 
with the recent bones of the pike, and not differing much from 
those of the cod. In this view, if we subtract from the caleare- 
ous matter actually found in the fossil bones, a quantity equal to 
that in the pike bones, and add the remainder to the siliceous 
matter, we shall obtain the following comparison, shewing a sin- 
gular resemblance. 
Bones. Bony rays. 
Pike. Gyracanthus. 
Phosphate of Lime, : ; ; : 55.26 53.87 
Carbonate of Lime, ‘ 6.16 6.16 
Animal Matter replaced in the Gijfecantinty by sili- \ 37.36 37.92 
ceous and calcareous matter, 
Phosphate of Magnesia, and Alkalies, Ei quantities. 
98.78 97.95 
I am aware, that if we adopt these last views, we must hold 
either, Ist, That the bony rays did not belong to a cartilaginous 
fish, in which class I believe the Cestracion is ranked, for the 
bones of cartilaginous fishes contain no bone earth; or, 2d, That 
the fin spines of cartilaginous fishes have a different constitution 
from the other bones, a point which I do not know has been yet 
investigated. 
Even when we view the composition of the coprolites im- 
bedded in the limestone, in combination with that of the recent 
fish-bones, we get something approaching to a coincidence. In 
one of my analyses of these coprolites, the ratio of the phosphate 
of lime to the carbonate of lime was about 8 : 1, and this does 
not differ very much from that of those constituents in the re- 
cent fish-bones, according to the analyses of Dumenii and Cury- 
rEuL. In the other coprolite which I analyzed, there is, on this 
view, an excess of about 5 per cent. of carbonate of lime, which, 
of course, was derived from the matrix. The phosphate and 
carbonate of lime form almost the entire mass of the coprolites 
from the limestone, the only other constituent of consequence 
being 2 or 3 per cent. of bituminous matter. 
