30 
The Queensland Naturalist. 
May, 1927 
From an inspection of a map showing only the course 
of the river, it would be impossible to pick out the site 
of the gorge, the course appearing to be quite unaffected 
bv the fact that a mountain happened to be in the way. 
The explanation is that when the Stanley first took its 
course the mountain, as such, did not exist. The granite 
mass was then covered, but as denudation progressed the 
granite became exposed, and being more resistant to 
denudation than the surrounding rocks, the latter have 
been denuded away, leaving the granite mountain up- 
standing. The powerful stream has been able to cut 
down its bed and form a gorge through the granite, 
while both above and below the gorge denudation has 
produced a more “mature” type of country in the softer 
rocks. Clearly the Stanley is older than at least part of 
Mount Brisbane. 
Turning now to the western and southern tributaries 
of the Brisbane, Lockyer Creek traverses in an E.N.E. 
direction a very wide alluvial valley from Helidon to its 
junction with the Brisbane, a wider valley than that of 
the main stream. It also meanders about a fairly direct 
line. 
Its Southern tributaries, Ma Ma, Blackfellows’, and 
Laidley Creeks have fairly regular courses northward. 
They are nearly parallel to the streams further east, 
which also take their origin in the main range, namely 
the Bremer, Warrill Creek, and Teviot Brook, the latter 
being part of the Logan River waters. Now, some 
geologists have suggested that in former times the Main 
Divide was further east, and that the shorter and more 
active coastal streams, cutting back their heads more 
rapidly than the western flowing streams, have caused the 
divide gradually to be shifted further west. Such a 
cutting would be rather promiscuous and unequal, one 
stream pushing ahead of or capturing its neighbours, 
and so on without anv parallelism. The long, roughly 
parallel streams w’th fairly regular courses coming from 
the main divide at an acute angle, hardly support this 
view. 
It has been suggested by other authorities that the 
Main Range, or at least part of it, is the result of the 
faulting down of the lower country to the east. On this 
explanation the courses of the streams are equally inex- 
plicable, as they seem to bear no relationship to the 
drainage of the other side of the range such as would be 
