80 
The Queensland Naturalist. August, 1935. 
related to a similar division in the extensive volcanic oc- 
curences in Victoria. 
This classification however, does not fit satisfactorily 
with what we found either at Numinbah or Canungra. The 
uppermost rock is basaltic, certainly, and in some parts, 
rhyolitic rocks occur beneath the latest basalt. Less com- 
monly basalts are found below the rhyoloitic rocks. The 
impression gained at Numinbah is rather of a complex 
of alternating types, than of a three-fold division. For in- 
stance, in a traverse up the valley, from near Numinbah 
to the border, we pass in sequence, from greywacke to 
rhyolite to basalt, to sandstone, to trachytic tuff, to sand- 
stone, to rhyolite, to basalt, and while on basalt at 1300ft., 
in the gap at the border, we have on either side, high cliffs 
of trachytic rocks surmounted by basalt up to 3500ft. and 
more. 
This sequence is not consistent with the three-stage 
view, and a similar complex was found by Mr. C. C. Mor- 
ton, at the head of Little Nerang Creek, on the eastern 
side of Springbrook. 
The structural relationships of some of the rhyolite 
is extremely puzzling. It will be recalled that in the 
Coomera gorge, near Canungra, which lies between Tam- 
borine Mountain and Beechmont, the rhyolite occurred 
in a belt, to the east of which the schists rise to elevations 
up to and over 1500ft., and to the west of the rhyolite belt 
the sandstone rises to 1000ft., while the bed of the river 
in the gorge is in rhyolite at only 200 or 300ft. above the 
sea. All three rocks, are capped by the basalt of Tam- 
borine to the north, and of Beechmont to the south, and 
wherever observed the contact of the rhyolite with the 
rocks on either side appeared to be very steep, approach- 
ing the vertical. To the north of Tamborine Mt. basalt, the 
rhyolite is again found in a similar position, namely, be- 
tween the schists and the mesozoic strata in Cedar Creek, 
and shows itself to the east of the basalt in Guanaba Creek, 
below St. Bernards. 
It was of especial interest to find that in the Numin- 
bah Valley the rhyolite emerges again from beneath the 
Beechmonth basalt capping, still occupying the same 
position between the schists or greywacke and the sand- 
stone. About a mile to the north of Numinbah we were 
able to locate the boundary with the greywacke, a very 
steep contact with the anpearance of a faulted junction. 
A traverse through the timber reserve a little nearer the 
camp, led us 300 or 400ft, up a hill, with rhyolite all The 
way, until near the top, where some greywacke outcrop- 
ped, but the very top was rhyolite, and under it some 
