LIMONITE AND LIMESTONES—GILPIN. 39 
We are, perhaps, not fully informed in the processes involved 
in the formation of the beds of Spathie ore. The Iron may be 
conjectured to have been deposited during the growth of the 
Limestones, and as a ferrous salt, to have been Carbonated by 
means of the decomposing organic matter which must have been 
present at that time. 
If now we imagine this great mass of ferruginous sediments 
formerly overlapping, more or less, the present exposures of 
Silurian slates of the district, we have a compound admirably 
calculated for the formation of the Limonite ores of the East 
River as they are now presented to our view. 
The precise manner in which this Limonite was separated, 
either from the Limestone, in which it formed a Carbonate, or 
from the shales which held it, probably as an Anhydrous ses- 
quioxide, and re-deposited, is perhaps not fully understood. 
Were the old outlines of the district restored, we would almost 
undoubtedly find the Pictou Coal field extending over this por- 
tion of it. The Carbonic acid dissolved in its waters from the 
decomposition of the vast masses of vegetable matter collected 
for the formation of our Coal seams, would furnish a most pow- 
erful agent which, charged with Iron as Carbonate, would pene- 
trate the underlying measures whenever access was allowed 
through faults, ete. 
We need not, however, draw upon this source. The ordinary 
per-centages of Carbonic acid present in the waters of our globe 
are amply sufficient for the changes we are contemplating, whem 
we consider the time allowed for its action. 
The water, charged with Carbonic acid, would take up the 
Tron in the strata as Bicarbonate, and filtering downward 
through the faults and meridional planes of the measures, would 
part with a portion of its Carbonic acid when it met the Lime- - 
stone, and then, depositing its insoluble Carbonate of Iron, would 
take up Limestone and pass away as Bicarbonate of Lime. 
Some of the Bicarbonate of Iron would also be decomposed 
in the cavities and fissures of the strata, with loss of Carbonic: 
acid, and the resulting insoluble Iron salt would be deposited.. 
The Carbonates of Iron thus thrown down as a distinct deposit, 
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