On the Norian or " Upper Laurentian " Formation. 197 



Calcite. — This was found only in two hand-specimens. 

 One of these was fresh and contained a little calcite, which 

 might possibly be a primary constituent. The other was 

 from New Glasgow, and in this the calcite, together with 

 zoisite, epidote, &c, appears as a decomposition product of 

 theplagioclase in the form of a dull finely granular mixture. 



Epidote. — The only locality where epidote occurs is also 

 near the village of New Glasgow. It is found in several 

 sections of the anorthosite from this place along with 

 chlorite and quartz as a product of decomposition of the 

 pyroxene, and as above mentioned with calcite and zoisite 

 as a product of decomposition of theplagioclase. In one or 

 two places it also occurs in small bands, cutting diagonally 

 across the anorthosite following the lino of small faults. 

 The epidote is everywhere secondary. 



Garnet. — This does not occur as a constituent of the 

 normal anorthosite, but is often found near its contact with 

 the surrounding gneiss. It has a pinkish color, and is seen 

 under the microscope in small irregular masses which are 

 often mixed with or which completely surround the grains 

 of iron ore. In the sections of the variety of anorthosite 

 rich in iron ore from the Township of Wexford, range I, 

 lot 7, (and from other places above mentioned), we find a 

 pale pink garnet which forms a small zone of uniform 

 breadth around every grain of iron ore or pyroxene where 

 these otherwise would come in contact with the plagioclase. 

 Between the pyroxene and the iron ore there is however 

 no garnet. It is quite isotropic and has grown out from 

 the iron ore or pyroxene into the feldspar, against which it 

 is bounded by sharp crystalline outlines. These zones of 

 garnet are analogous to the zones of actinolite and hyper- 

 sthene around the olivine of the anorthosite from the 

 Saguenay River which will be referred to later on and 

 which have also been described in olivine gabbros of many 

 other localities. 



Zircon. — This mineral is not found in the normal 

 anorthosite but it occasionally occurs in this rock near its 

 contact with the gneiss. It is seen only in small quantity, 



