314 Messrs. Jackson and Alger on the 
surrounding iron, assisted, as we have before ventured to say, 
py heat. 
The existence of the sulphate of lime in the ore, although it 
is no direct proof of the action of heat upon it, yet has a bearing 
on the case. For it can hardly be overlooked, that the sulphur, 
which was at first united with pyrites of which there are yet tra- 
ces in the ore, has, by its decomposition and passage into sulphu- 
ric acid, united with the lime of the shells, and thus given rise to 
the sulphate under the form we have described ; leaving the iron 
of the pyrites behind, as we find it, in a yellow oxide. This pro- 
cess, we are aware, might have taken place, as it does take place, 
without much heat; but all the attending phenomena are such, 
in the present case, as to leave but little doubt in our minds, that 
heat was the agent employed. But, in addition to these, we have 
other arguments in support of these views, which, to some, may 
appear of a more positive character than those already adduced. 
It is wellknown that iron is deposited from an aqueous solution only 
in the state of the peroxide, and that its ores, in such cases, are 
never of a great specific gravity, and always void of magnetism. 
Now the aqueous origin of the ore in question, is evinced by the 
presence of marine exuvie in every part of it; yet, in some pla- 
ces, even where the fossil remains are the most numerous, this 
ore has acquired the character of the magnetic oxide, and is no 
ionger a peroxide. How then is this to be explained? how is it 
that the ore assumes such totally different characters in different 
parts of the same bed? that of Pictou being in the state of perox- 
ide, as it was originally deposited from an aqueous solution, and 
that of Clement’s in the state of the magnetic or protoxide. We con- 
ceive it undeniable, that this great change is to be ascribed to the 
heat attending the production of the trap rocks of the North moun- 
