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[Assembly 
rection at the surface, nearly or quite parallel to the strata in the direc- 
tion of their length, yet cut or cross them in a downward direction, or 
in other words, their dip differs from that of the rock. These would 
undoubtedly be considered as instances of veins. From considerations 
of the kind which I have specified it is clear, that most, if not all of 
the repositories of the magnetic oxide, are veins and not beds. Theo- 
retical considerations, lead to the same conclusion, for it is difficult to 
resist the doctrine, that they have been formed in a manner analogous 
to veins, and the veins in primary rocks. That they have no analogy 
at all, to those beds of hematite, of the Green Mountain range, in 
Massachusetts and Vermont, or to the argillaceous oxide, of the pro- 
tean group of rocks, in New- York, is quite evident. These are de- 
posits of ferruginous matter, in irregular masses, and may be entirely 
exhausted or removed from the courses in which they lie. It is in this 
point of view, that the determination of the question, now under con- 
sideration, is important, inasmuch as veins extend to an unknown depth, 
and no instance has occurred, in which in the course of exploration, the 
mineral matter has been entirely removed. We may confidently expect 
therefore, that a vein of a given width, will furnish a certain amount 
of ore, at a depth not too great to become inaccessible. Even calcu- 
lations may be made of the tons of ore which the vein will yield. 
If then, the masses of magnetic oxide are veins, and are also ana- 
logous to veins of limestone and granite, (and of this there is scarcely 
a doubt,) then we may infer, that still larger masses exist in the inte- 
rior of the earth, to which the veins lead, and in which they terminate. 
This inference, is supported by the phenomena, which the great veins 
at Mclntyre present, and which will be noticed in the sequel ; again, 
if this is true, then the magnetic oxide is one of the constituent rocks 
of the globe, and ought to be described as such, and as it appears be- 
neath the hypersthene rock, which is a variety of granite, it ranks 
lower in the series than the latter. Geologists may differ, as it regards 
the importance oT these remarks; I shall therefore, pursue them no 
further. 
SECTION VI. 
General remarks in relation to the veins of Magnetic Oxide, as they 
occur in the Northern Counties. 
Occurring as this substance does, over a wide extent of territory, 
and also in formations somewhat dissimilar, it is not unexpected to find, 
