T42 NEW YORK STATE MUSEUM 
general parallelism throughout a zone of less than a foot verti- 
cally, just above the footwall, as can be seen near the center 
right of plate 1. Furthermore the plates are parallel with the 
major divisional planes of underlying marble. But this parallel- 
ism of the plates with the underlying structures or within the 
vein itself can only be found occupying a few square feet. Such 
a structure would seem to indicate for a portion of the vein, if 
not for the entire vein, a shearing frictional movement between 
the walls of the original Grenville — presumably a fine-grained 
marble which was not unlike that of the hanging wall. This 
sort of movement might very well have taken place generally 
and at first throughout the fracture zone producing a general 
parallelism of the plates of which this particular spot is all that 
remains. Farther down the dip, by a few feet, may be seen a 
sinall anticline of banded or platy structure, as though a compres- 
sional movement was also in part responsible for a part of the 
structure but followed that of the shear. The most conspicuous 
feature of the vein in this regard is the utter lack of parallelism 
of plates for any considerable distance either vertically or hori- 
zontally and the dominance of the platy breccia and the cellular 
structure, as though, after the plates had been sheared, they 
became separated from the parent rock and fell in a hit or miss 
fashion into the break where the original fragments and plates 
of carbonate (marble) eventually became replaced in part by the 
dark carbonate and quartz, forming the breccia cement. This 
irregularity in the arrangement of the plates might have been 
produced by a crushing following the suspension of the shear; 
but whatever movements were responsible for this mass of inter- 
secting plates, the result has been to make the fracture and its 
contents a favorable place for the deposition of mineral matter. 
Mineralogy of the Box Vein 
The minerals thus far observed in this vein are quartz, man- 
ganiferous calcite, pyrolusite (dendrites), chalcopyrite with its 
alteration products malachite and limonite, sphalerite, smithson- 
ite, kaolin, vermiculite and asphaltum. Galena has been reported 
to have been found. Most of these occur either in the boxes or 
directly associated with other structures. 
Quartz. This is perhaps the most abundant mineral of the 
deposit and is usually found in aggregates of well-crystallized 
singly terminated forms lining the boxes or comb structures. 
