282 Dr Andrew Fleming on the 
contains phosphoric acid, in the proportion of } per cent., 
and a little carbonaceous and bituminous matter. The iron 
being a protoxide, the fresh fracture is black ; but, by ab- 
sorbing oxygen, it becomes yellow, and the phosphate passes 
into a perphosphate, becoming blue. Thus the fish are 
visibly marked with blue streaks on a yellow ground.” 
The small quantity of ‘“ carbonaceous and bituminous 
matter” referred to in the preceding analysis, seemed to in- 
dicate that the organism, though probably of the same 
species (for those which I principally examined, likewise 
appeared referrible to Dipéterus, although the Cocosteus was 
also among the number of the most completely mineralized 
remains), had been subjected to peculiar influences. I 
could not, indeed, avoid suspecting that, even in the most 
thoroughly altered organisms of Stromness, the original 
animal matter had not been removed to so great an extent. 
Under this impression, the most completely mineralized 
portions were selected as the subjects of experiment, and 
they exhibited the following external characters :— 
Colour, jet black, with a shining resinous lustre ; in some 
cases inclining to vitreous; fracture more or less con- 
choidal ; hardness = 3 of Mohs’s scale, sp. gr. = 1.517; 
the powder is of a brownish-black tint. 
The general appearance of the mass bears a closer resem- 
blance to cherry-coal than to any of the other varieties of 
that important mineral, and may, with some degree of pro- 
priety, be denominated animal cherrycoal, in contradistinc- 
tion to that which occurs in beds in the coal formation, and 
appears to be of vegetable origin. 
When a small piece of the coal was heated in the open 
air, on platinum foil, it took fire, and burnt with a white 
flame, leaving a considerable residue of a light-grey ash. 
The coal in powder, when heated in a glass tube over a 
spirit-lamp, evolved copious white fumes ; and a yellow oil of 
a strongly bituminous odour was sublimed, which concreted 
on cooling. Litmus paper, moistened, and held in the tube, 
indicated an acid reaction. Being desirous to ascertain if 
any nitrogenized matter was contained in the coal, another 
portion of the powder was heated with a strong solution of 
