May, 1927 
The Queensland Naturalist. 
31 
expected on that hypothesis. There is, moreover, one 
piece of evidence which seems to me to be very clearly 
against it, in addition to those already put forward on 
geological grounds by writers disagreeing with the 
hypothesis. 
Reynold’s Creek, a main head of Warrill Creek, rising 
in the Main Range, traverses moderately hilly country 
for some twelve miles, when it comes to Mount Edwards, 
2300 feet high. 
This is one of those prominent trachyte mountains so 
characteristic of the Fassifern and East Moreton districts. 
It is situated directly in the course of Reynold’s Creek, 
which is here 392 feet above sea level. Instead of being 
diverted by this mountain of exceedingly hard rock, the 
creek goes right through it, cutting it into two' by the very 
beautiful gorge. 
The position is very closely similar to that of the 
Stanley River cutting through Mount Brisbane. Again 
an inspection of the river course on the map fails to 
show any peculiarity at this place; it seems to go on its 
way quite unaffected by the existence of a mountain of 
hard rock right in its path. Again we are driven to the 
conclusion that when the stream originated the general 
level of the country was above the present top of Mount 
Edwards, and that there must have been here a valley 
rather than a mountain. These trachyte plugs, such as 
Mount Edwards, are usually regarded as the cores or 
necks of old volcanoes. If this is so the volcano must 
have been flattened out so as not to form even the 
slightest elevation, or else have been covered up by some 
subsequent deposit when Reynold’s Creek started its 
career. Knowing as we do how the hard trachyte resists 
weathering at the present time, and on that account forms 
mountains, we may be certain that the volcano was not 
flattened out by denudation. The trachyte is generally 
thought to belong to the Tertiary epoch, and we have no 
reason to suspect that it can have been covered over by 
any later sedimentary deposits. There is. however, quite 
a possibility that it may have been covered over bv former 
eastward extensions of the basalt flows of the Main 
Range, for these are known in places to cover traehytic 
rocks. 
If the basalt formerly covered Mount Edwards, which 
is even now, after much denudation, 2300 feet high and 
about the height of Spicer’s Gap, it is clear that there 
'Cannot have been any appreciable down-faulting of the 
