The ores and their associated rocks have in some cases been deformed by 
stresses which have resulted in faulting, both of Appalachian and of Triassic 
block types. In a few of the mines the ore bodies have been more or less 
seriously affected by such movements. 
Fig. 1 Deformation exhibited by step-faulting and crushing. Hanging 
wall in small pit, Bull mine. The rock is Pochuck-Grenville, consisting of 
hornblende, plagioclase ranging from oligoclase to andesine, subordinate 
crthoclase and a little quartz. Light polarized, nicols crossed, X 35. 
Fig. 2 Represents a crush-zone in the Bull mine. Syenitic facies of 
Pochuck. The feldspar is alkalic, and the ferromagnesian mineral is a green 
pyroxene. The dark area is a mixture of crushed pyroxene, crushed 
magnetite and fragments of feldspar. Ordinary light, X 35. 
Fig. 3 Crush zone between main ore body and hanging wall, Canopus 
mine. Quartz, showing strain shadows, and crushed and sericitized feldspar. 
A post-ore shear zone. The ore body has likewise been severely affected. 
Polarized light, nicols crossed, X 35. 
Fig. 4. Primary deformation, or protoclastic structure; rock from Theall 
tunnel, Croton Magnetic mine. Granulation of the margins of the grains, 
bent grains, wedge twins and strain effects are due to movement before com- 
plete solidification was effected. The magnetite here is interstitially dis- 
tributed, replacing in part and cutting the ferromagnesian minerals, and the 
feldspars. The rock is a syenite, and is judged to be related to the syenitic 
facies of the Pochuck. Light polarized, nicols crossed, X 35. 
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