CHARACTER OF THE METALLIFEROUS VEINS, 
139 
CHARACTER OF SOME OF THE METALLIFEROUS VEINS OF 
THIS COUNTRY. 
§ 91. Veins of magnetic and specular oxide of iron. We 
have not as yet placed a due estimate upon the value of 
the iron ores of this country. The increased and increasing 
use of iron itself, together with the demand which grows out 
of our increasing population, are facts sufficiently positive 
and absolute to prove that the wants for this metal will soon 
more than double its present consumption. We have seen that 
our ores are abundant and favorably situated to supply the 
wants of the country. I need not dwell upon this topic. My 
object is to illustrate the formation and structure of the reposi¬ 
tories of these ores, and in doing this I shall compare them 
with some of the oldest iron mines of the old world. 
The magnetic iron veins are upon a magnificent scale, es¬ 
pecially those in northern New York, to which I shall direct 
the attention of the reader. 
The repositories of this ore seem to be of two kinds. Of 
one kind I have no hesitation in saying that they are veins ac¬ 
cording to the definition usually given. Of another kind there 
may be doubts whether they are veins or beds, but I have re¬ 
garded them as rocks or masses of magnetic iron, inasmuch as 
their boundaries with the rock are indefinite, and they are upon 
so large a scale that they are worked like quarries of marble or 
granite. 
The structure of the veins of iron scarcely differ from those 
of other metals. The ore itself is crystalline, and there is no 
doubt but that it is pyrocrystalline. It is not subject to great 
changes in its composition. The veinstone, however, is often 
stained red or brown, by a change of the protoxide into the 
peroxide; such a change is regarded as a favorable indication 
of the quality of the ore. 
In veins of magnetic iron the rich part of the ore forms 
a belt parallel to the walls, and it occupies very frequently the 
