PLATE 27, 28. 
tures, exhibiting a fibrous, ramified texture, not unlike that 
of some of the Jlcematites iron-ores — Each fracture is also 
marked with regular, elevated, parallel, transverse, lines, 
generally of a darker colour than the rest of the stone. 
This fossil, from the organic appearance of its structure, 
has been mistaken for a petrifaction. — That it is not one, 
will be evident, if we maturely consider its form and com- 
position. — The internal structure of organized bodies, ani- 
mal or vegetable, always differs essentially from the external 
figure. But, in the fossil now under consideration, the 
minutest particle, when examined by a glass, exhibits, in 
miniature, the same ramified, conical, and transversely 
striated appearance, that pervades the whole mass, or any 
of the parts it may be broken into. We, therefore, con- 
clude, the origin of this stone to be no more organic, than 
that of Fibrous Gypsum, Spars, and other regularly formed, 
native fossils. 
This ironstone, when first got, is of a deep brown colour, 
in a few days the surface changes to a bluish grey, tinged 
with yellow — It effervesces with acids ; grows black in the 
fire, and is then attracted by the magnet — It probably con- 
tains Manganese. 
