like massive quartzites. They form the majority of the 

 types in the Palaeozoic beds and their pedogenesis is 

 exceedingly difficult to follow. In some cases they appear 

 to be the products of metasomatic replacement of sedimen- 

 taries, in others they may be much metamorphosed erup- 

 tives, but the distinction is hard to define. 



1. Actinolitic Conglomerate Schist, Stokes' Point. 

 Macroscopic. — In hand specimens a handsome rock, the 



radiating aggregates of actinolite standing out on a light 

 grey background. The sericite can be made out with a 

 pocket lens. The rock is decidedly schistose and the 

 included pebbles have been drawn out. 



Microscopic. — Actinolite, quartz, magnetite, sericite. 

 The actinolite is in porphyroblastic aggregates, feathery 

 and curviform, also in shreds in the groundmass. The 

 quartz forms the matrix in a very fine-grained mosaic, the 

 granules separated from each other by shreds of sericite 

 and actinolite. The magnetite in line grains and aggregates 

 throughout the section. 



2. Sericite-quartzite, Ettrick River. 

 Macroscopic— A massive grey rock of even fine grain, a 



little sericite can be distinguished with a pocket lens. 



Microscopic. — Quartz, plagioclase, sericite, biotite, zir- 

 con. The quartz forms the bulk of the groundmass in small 

 clear grains interpenetrating the felspar, which is undecom- 

 posed but crowded with inclusions, a few grains show 

 multiple twinning. Biotite in shreds througbout the slide 

 much altered to chloritic material, in places intergrown 

 with the sericite. Zircon in numerous small irregular 



