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where found in place, has its fibres at right angles to the 
walls of the vein. The veins range up to four inches (-1 
m.) in width. 
Osann describes a gabbro from this locality [2], which 
has many features in common with the gneiss capping the 
hill at the main pit. This rock is coloured as gabbro on 
the map. 
At a point above the smaller mill-pond, Grenville 
limestone is intruded by a small patch of pegmatite, which 
AVAVANA GND ONT Phlogopite, showing cleavage planes 
Pegmatite with graphite 
Grenville limestone 
Radially arranged phlogopite rim between graphitic pegmatite and Grenville 
limestone, Walker mine. 
carries graphite within its mass, and is separated from the 
limestone by a rim of phlogopite in which the flakes of the 
mica are set at right angles to the margin of the pegmatite 
block. 
Graphite was first shipped from this locality in the 
seventies, but at that time only columnar graphite was 
