08 PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND, 
highly tourmalinised schist’ made up of “ fine needles of 
tourmaline set in a matrix of fine crystalline muscovite.” 
These bands, beyond doubt, represent fragments of very 
highly altered country rock “‘ which was probably a diorite 
or a chlorite schist,” and which was “ first in part made schis- 
tose by dynamic metamorphism.” 
The rock which most nearly approaches in structural 
characters the Enoggera rock seems to be that described by 
Flett®® from Cornwall as ‘“tourmalinised slate (E1759), 
Belovely Beacon,” a microphotograph of which is shown and 
which is described as “a secondary aggregate of quartz and 
schorl which has replaced the original slate,’ and in which 
“the cleavage and slip-cleavace of the slates are perfectly 
retained.” 
The writer has in an earlier section commented on the 
remarkable similarity in structure between the albite-tour- 
maline rock of the Enoggera area and the unaltered Brisbane 
Schist. In 1914 he wrote: “‘ The whole schist has been so 
beautifully replaced that the new rock under the closest 
scrutiny shows every characteristic of the normal schistose 
structure.”*6 As the result of further investigation he sees no 
reason to modify that statement. The schistosity shewn in 
this interesting contact rock is undoubtedly older than and 
for the most part independent of the contact metamorphism. 
(VI) CONCLUSION. 
1. The rock described is almost on the contact of the 
Enoggera Granite with the Brisbane Schist. 
2. Mineralogically it is almost unique, consisting as it 
does almost entirely of tourmaline and albite. 
3. Practically no quartz is present, but a chemical analysis 
of the albite shows remarkable excesses of both silica and 
alumina. 
4. Structurally the rock is remarkably like the unaltered 
Brisbane Schists, the tourmaline of the altered rock corres- 
ponding in position and amount with the micaceous part of 
25 Petrological Notes in ‘‘ The Geology of Bodmin and St. Austell,” 
1909, p. 187. 
23 Ooch. Ula palas. 
