Fig. 1 Ore from the Lake mine, 2500 foot level. Thin section, light 
polarized, nicols crossed, X 35. 
Remnants of unreplaced rock (Pochuck-Grenville), consisting of pyroxene, 
hornblende, (both affected by serpentinization and carbonation), feldspar and 
quartz. The black area is magnetite. 
Fig. 2 Ore from the Canopus mine. Thin section, light polarized, nicols 
crossed, X 35. Magnetite (black) replacing Pochuck-Grenville. Extensive 
sericitization of the feldspars accompanies the replacement here, and even 
the quartz exhibits replacement aureoles. 
Fig. 3. Rock included in and surrounded by the ore, sixth level, Forest 
of Dean mine. Pochuck-Grenville, in part replaced by magnetite (black). 
Light polarized, nicols crossed, X 35. Note the replacement aureoles of seri- 
cite surrounding both quartz and feldspar remnants. Dark gray to grayish- 
black areas are quartz and feldspar. 
Fig. 4 Roof pendant in east lobe of ore body, Forest of Dean mine. 
Modified Pochuck-Grenville, which in part has been replaced by magnetite 
(black). Light polarized, nicols crossed, X 35. Rock is composed of color- 
less pyroxene, feldspars ranging from alkali perthites to moderately basic 
plagioclase, biotite and quartz of the Pochuck-Grenville, soaked with syenitic 
facies of Pochuck (note marginal relations) and invaded by dioritic 
pegmatite. 
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