.May, 1927 
The Queensland Naturalist. 
29 
It does not seem likely, therefore, that the course of 
the Brisbane has been kept along the boundary of the 
schists merely by their resistance, whatever other reason 
there may be for it. 
The tributaries on the western side of the upper 
Brisbane, namely Cooyar, Emu and Cressbrook creeks 
coming from the tableland, are roughly parallel, and run 
north-east to join the main stream. They are parallel to 
tributaries of the Burnett waters, draining the same table- 
land further north, and suggest being part of the one 
older drainage system now cut off by the newer formed 
upper Brisbane, and diverted into quite a different 
direction. 
The Stanley is the only large tributary on the eastern 
side of the upper Brisbane, and its basin is as puzzling as 
interesting. Rising in the southern end of the Blackali 
Range it is a not inconsiderable stream at Peachester, m 
a fairly wide valley. Here, at an elevation of somo 
500 feet in soft sandstone country, it is less than a mile 
from, and only about 100 feet below, the divide which 
separates it from the much lower coastal watershed. Its 
water, instead of continuing in its initial direction east- 
wards to the sea, distant only about 12 miles, turns sharply 
to the west and south-west to join the upper Brisbane, 
with a distance to travel of approximately ISO miles 
before reaching the sea. 
No satisfactory explanation of this is offered. One 
might suggest that the basalt of the Blackali Range 
formerly extended further south, and that the stream was 
diverted by it, or perhaps formed on the basalt, but this 
is not a very satisfying explanation, and it is remarkable 
that its neighbour, to- the north, Obi Obi Creek, takes a 
similar turn away from the coast to join the Mary River. 
There is clear evidence in the lower part of the 
Stanley that the topography when that stream was first 
formed was not at all similar to the present. Mount 
Brisbane, 2700 feet high, and little Mount Brisbane, are 
formed of one mass of fine-grained granite. This mass 
has been cut through by the Stanley in the gorge which 
separates the two mountains and forms the site of the 
proposed dam for the water supply of Brisbane. 
The Stanley, running through a wide vallev in 
country of soft rocks, appears to meander into and cut 
through the mountain of hard granite, instead of avoiding 
it altogether by taking a similar meander in the opposite 
direction. 
