UNUSUAL TOURMALINE-ALBITE ROCK FROM ENOGGERA. 59 
the unaltered schist, while the felspar veins of the former 
correspond in number and type with the quartz veins of the 
latter. 
5. In order to explain (I) the association of tourmaline 
and albite, (IL) the absence of free quartz, and (III) the struc- 
tural nature of the rock, the following hypothesis is advanced :— 
The micaceous parts of the schist have been metasomatically 
replaced by tourmaline, and the excess silica, together with 
that of the quartz veins has been removed to be redeposited 
elsewhere. Following this alteration, albite was introduced 
from the granite and deposited among the veins vacated by 
the quartz and in any interstices in the matted tourmaline. 
