REPORT OF THE DIRECTOR, 1922 137 
vein before the main infilling. It is maintained in this paper that 
the original plates or bands consisted of the Grenville marble or 
as Doctor Clarke (3) has observed of the “ thin calcareous lining 
of the fissure which by shearing or other stresses were scaled off 
as a veneer” and replaced and cemented by manganiferous calcite 
and quartz carrying several other minerals, as will be seen later 
on, all forming a most unusual sort of cellular breccia. 
It is not known whether or not the original break in the marble 
and its subsequent filling were separated in point of time but if 
they were approximately contemporaneous, and they might very 
well be, then these events were produced at a time when these 
ancient metamorphic rocks were subjected to great mountain- 
making movements and long periods of denudation. These resulted 
in the change of position of the rocks from the deeper zone of flow- 
age to the higher and more surficial zone of katamorphism where 
fractures and their cementation by the products of silicification and 
carbonization are among the most important characteristics. 
As further evidence of the high vertical position of this vein 
in the earth’s crust what is believed to be a horse of Grenville 
marble occurs at the north end of the vein and is very much fluted 
by the action of ground water where the line of demarkation 
between the vein and horse is a crescentic or cuspidal curve. The 
position of the horse and its relation to the vein would show that 
either through the action of ground water or the stresses which 
produced the fracture and breccia this block may have become worn 
off from the wall rock or broken off and fell into the fissure, later 
to become incorporated within the cementing breccia. 
Structure of the Vein and Its Contents 
Some of the characteristic structural features of the vein have 
already been referred to and the same illustrated as in plates 1, 2 
and 3. To understand more thoroughly the structure of the vein 
it will be necessary to study the vein and footwall section as given 
below: 
Cie rasen BYRACEL OF [DOES SHS Ssacoaobacanoduc hienteet 
Gaara. Coarse reddish pink marble.......... .5 feet 
(il Sao be SilicinedmGrenvallepimanblense sae aa eee .8 feet 
DE aise Binks imarblemwathmcaleiterns yeene even: .85 feet 
OSes CoM Gran Werle wal wet, oo beds chee eae 3 feet 
to aoeoo NM ate eunel joxrmle ie OE 4 big oo ona cd seo 4 feet 
ieuay, Craveiia ri blem ace bas peice eatin aes coats feet 
dja...... Decomposed and disintegrated marble Tue et 
