46 OF METALLIC VEINS. 
been spread out in a liquid state over the surface of the earth, and 
thus placed in a condition to enter and occupy the fissures in 
which they now appear, large collections of them would have 
been formed by reason of their high specific gravity, in those 
basin-shaped cavities which occur frequently in every country, and 
in which nevertheless we never find them. Indeed, nothing can 
be more crude and preposterous than the theory of Werner, in 
regard to the formation of veins. 
The theory of Hutton, which represents them as produced by 
the consolidation of the material of which they are composed, 
forced in a state of fusion into fissures, previously existing in the 
strata, by a force operating from below, though appearing at first 
less encumbered with diffculties, has but little the advantage of its 
rival. This violent and tumultuous entrance of the materials of 
the vein, is totally inconsistent with that perfection of crystalliza- 
tion which is often witnessed in the different substances associated 
in its composition. In the Southampton mine, just referred 1o, 
the sulphuret of lead instead of being scattered in shapeless masses, 
through the whole extent of the gangue, is collected into large and 
well defined crystals, perfectly distinct from the quartz in 
which they are imbedded. That where a vein passes through 
two or more strata of different composition and character, its 
width and productiveness vary along with the rock in which it lies, 
is another fact that is calculated to render the soundness of this 
theory doubtful, even if it should not be regarded as altogether 
fatal to it. Of the examples that have been noticed and recorded 
of this kind of dependence, tw r o only will be cited. 
1. In the north of England there is a body of stratified rocks 
that is rich in the ores of lead. It is divided into fifty-five distinct 
beds, exhibiting three principal varieties of composition and struc- 
ture Nine of these beds are limestone, eighteen siliceous sand- 
stone, and the rest shale, with thin beds of imperfect coal. The 
different kinds alternate with each other. The veins traverse 
them all, and have been worked more or less in all of them, but 
the ore is found abundantly only in particular beds. When the 
veins pass through the shales, they yield very little, if any, ore; 
in the sandstone they are more productive — are richer still in 
the limestone, but it is a single bed called the great limestone, 
that has yielded four-fifths of all the metal drawn from the veins 
of this distict. 
2. A vein of quartz traversing argillite in the north-western 
part of Montgomery count} 7 in North Carolina, was found to be 
rich in gold. The owner (Barringer) with the assistance of his 
family, obtained from it six pounds of gold, worth about sixteen 
hundred dollars in the day after it was discovered. But the ar- 
gillite here forms only a superficial covering on the top of another 
rock. As soon as the vein passes from this into the suhjacent 
stratum, magnesian limestone takes the place of the quartz, and 
it ceases to be auriferous. Other examples might be cited especi- 
