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Prof. Beck on Igneous Action, as exhibited in New York. 343 
In reviewing the facts set forth in this paper, we arrive at the 
following conclusions, viz. : : o 
1st. That if it is admitted that the original protrusion of granite 
was due to igneous action, and if to this is to be ascribed the 
crystallization of the minerals found in the primary beds and 
strata, these must in many cases have been a second time sub- 
jected to a high temperature,—high enough at least to cause the 
partial fusion of these minerals. 
- 2d. That at later geological periods the presence of water be- 
came another, and perhaps new condition, of the great igneous 
agency, and that hence serpentine with its large proportion of 
water was one of the results. 
3d. That the presence of water, known to be an almost invari- 
able condition of modern volcanic action, is proved to have been 
no less so during the periods when the eruptions of the trappean 
rocks took place. 
Finally, I have endeavored to show that as we proceed to the 
interior of the earth there are arrangements of mineral forms — 
quite different from those which characterize the lowest of the 
primary rocks as they appear on the surface. Now I think it 
conceivable that the character of the igneous eruptions may have 
been connected with circumstances attending the different depths 
to which the refrigeration, and consequently the solidification of 
the crust may have extended. When the granitic deposits had 
been but partially solidified, fissures and cracks in the crust would 
be followed by injections of the same mineral ingredients, in 
some instances perhaps sparingly mixed with those below. Hence 
the formation of true granitic veins with their accompanying 
minerals, during such a state of things, might be easily accounted 
for. But as the solidification extended towards the interior, the 
erupted matter would exhibit a different aspect, owing perhaps in 
part to the new agencies which were brought into action, but 
chiefly to a real difference in the mineral matter or composition, 
which we have reason to believe exists in different parts of the 
central nucleus, or at different distances from the surface. 
