137 
hibit ossified processes developed along the two flattened 
edges of the ray, which served to support the gills. 
The ossified walls of the air bladder are occasionally 
found ; one specimen in my cabinet is nearly six inches in 
length by three in breadth. 
LABYRINTHODONTS. 
Vertebrae and other bones of labyi'inthodonts recognised 
by L. C. Miall, Esq., as those of Loxomma have been found. 
They are rare. 
THE MINERALS OF THE YORKSHIEE COAL-FIELD AS APPLIED 
TO THE MODERN MANUFACTURE OF IRON. BY BENJ. 
HOLGATE, ESQ. 
The large quantity of Iron, that in the form of oxides 
and carbonates, combined with earthy matter, is found 
distributed over the world, and in every Geological forma- 
tion, is frequently unutilized owing to the want of means for 
reducing it to the metallic state. Its reduction into the state 
of pig, or that in which it may be cast into any required 
form, and its manufacture into the malleable state and steel, 
so that it may be worked under the hammer or drawn out 
by means of rollers into bars, is dependent upon the means 
of obtaining fuel, a large quantity being required for its 
manipulation, and upon a plentiful supply of substances, 
not fusible at high temperatures nor chemically acted 
upon by either the fuel or the Iron in a state of fusion. 
Thus the Iron-ore of Spain, though of no use in that 
country, is brought to England in large quantities, and 
mixed with the ores of this country. The oolitic and liassic 
ores of North Yorkshire would be less valuable were they 
