454 
WISCONSIN STATE AGRICULTURAL SOCIETY. 
be changed into quartzite or quartz rock; and our magnesian 
limestone into serpentine or some other form of metamorphic 
rock. 
The fissures, faults and dislocations in the rock produced by 
this plutonic action (or form of mechanical force) would neces¬ 
sarily cut through the strata vertically, or nearly so, and to a 
great depth ; thus permitting the rise of metalliferous vapor or 
fluids wdiick may be generated in and by this heated mass be¬ 
low. Here we see distinctly the relation between this form of 
mechanical force acting through melted matter as a medium, 
and the peculiar phenomena presented in the strata in which 
and through which it has acted. The protruding of igneous 
masses, the metamorphic action, the displacement of prior- 
formed strata, the faults, dislocations and fissures in the dis¬ 
turbed and altered rocks are the known results of this form 
of force. 
But suppose again, that this elevation of igneous matter had 
taken place beneath the waters of the ocean, where stratified 
rocks had commenced to form over these faults and disloca¬ 
tions in the earth’s crust extending down and communicating 
with the heated region below, and through which metalliferous 
vapors and fluids were rising and would continue to rise, what 
would be the result ? In the first place, there would be a 
change or transformation of mechanical force ; it would be no 
longer plutonic, that is, acting through melted matter as a 
medium, but hydro-plutonic, acting through water. In the 
next place, a change in the form of the force would be follow¬ 
ed by a change in the form of its result. Hence, between fis¬ 
sures produced in rocks by plutonic action, and those produced 
by hydro-plutonic action there would be a line of distinction, 
and we often find them presented to us in nature as two classes 
of fissures. 
A moment’s reflection on the conditions bringing about this 
change in the forms of force, and their results, will enable ns 
better to understand the modifications and diversity in the 
forms of the two classes of fissures. 
These masses of melted matter forced up through prior 
