Mineralogy and Geology of Nova Scotia. 313 
ore. It is probable that remains of this fossil, much larger than 
this, will yet be met with in the slate, or inits included beds of 
transition limestone ; as rocks similar to these have hitherto fur- 
nished the most remarkable that have occurred in Europe, some 
of which, found in the slate rocks of France, are, according to Pro- 
fessor Bakewell, seven inches in length.* They are found also of 
of equal size and in great perfection at Trenton Falls ; and it is 
remarked by Professor Silliman that ‘some of them seem almost 
looking out of the black limestone rock, as if still animated.” + 
Those found in the Dudley limestone, according to Parkinson, 
rarely exceed three inches in length. 
In breaking masses of this ore, the fracture frequently crosses 
the fossils, and lays open their inner surfaces, which are often 
covered by a very thin and brilliant, bluish-green, botryoidal 
crust of the phosphate of iron. They also present this substance 
crystallized, in beautiful divergent plates, or lamine, which 
are translucent and of a bluish-green color; also lamellar sul- 
phate of lime shooting through the cavities from one side to 
the other. In some cases, the cavities, left in the ore by the 
decomposition of the internal part of the fossil, are entirely filled 
up with a yellow friable carbonate of iron, having, intermixed with 
it, a few bluish spots of the phosphate ; at other times the crusta- 
ceous parts of the fossil are converted into carbonate of iron, which 
shows, distinctly, the original appearance of the shelly covering. 
In fact, in almost every fossil met with in this ore, we have one 
or both of these metallic salts, produced by the combination of its 
constituent principles, carbonic and phosphoric acids, with the 
* Introduction to Geology, p. 27. 
t See note on page 48 of his “‘ Outline,’ appended to his edition of Bake- 
well’s Introduction. 
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