THE PETBOGBAPHY OF SOME QUEENSLAND OIL SHALES. 131 
light the whole clay matrix shows a strong brownish-yellow stain. Scattered 
through this matrix are small, irregularly-shaped, organic masses of a dark 
brownish-red colour. This material, which may reasonably be classified as 
semi-opaque attritus derived from the decay of vascular tissue, makes up 
from 10 to 15 % of the rock. Some of these organic particles have been found 
to show good cell structure, particularly in the horizontal section. They vary 
considerably in size, being never more than 04 mm. in length and usually much 
less. These vascular fragments in the rock are, in fact, in various stages of 
maceration, and some of them are very nearly opaque. As well as this material 
a few small, pale yellow, translucent bodies, similar in all respects to the gelosite 
bodies of torbanite, have been recognised. They appear elongate in the vertical 
section and roughly rounded in the horizontal one, but they are much more 
widely spaced than in any torbanite. As gelosite bodies are known to be the 
fossil form of a colonial, unicellular alga, it is apparent that this oil shale is 
partly of algal origin. Most of the organic matter in the thin sections, however, 
is translucent humic matter and brown-opaque attritus. No animal remains 
were recognised in the thin sections. 
A few small grains of quartz and flakes of mica were sVeen within the 
clay matrix. They have not been affected by the yellow organic stain and appear 
clear and white under ordinary transmitted light. Pyrites is quite abundant 
in the rock, occurring both as very minute crystals scattered through the matrix 
and also as fairly large aggregates. 
In the vertical section the parallel orientation of the organic bodies and 
the inorganic constituents can clearly be seen. 
From the very large amount of mineral matter, and the small amount 
of organic matter seen to be present, it is apparent that the rock is a low-grade 
oil shale. 
Chemical Analysis. 
A proximate analysis of this sample has given the following result : — 
Moisture 
Volatile Matter 
Fixed Carbon 
Ash 
6-3 % 
20-2 % 
5-2% 
68-3 % 
Chemically this indicates a low-grade oil shale, which agrees with the 
determination obtained from the petrological examination of the rock. 
CONCLUSION. 
From the above descriptions it is clear that the Alpha and the Carnarvon 
Creek torbanites are very distinct petrologically from The Narrows and the 
Strathpine oil shales. A striking similarity between the two latter oil shales, 
however, has become evident. They have been found to be almost identical 
in macroscopic and microscopic appearance, and in their physical properties. 
The close petrological relationship between them is also reflected in their 
