112 PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND. 
material is very similar to that of the Eight Mile Block. 
The relationship between the strike of the flows and the 
direction of the ridge is very marked. 
(wi.) Stanthorpe Road Block—This is about 10 miles 
south of Warwick, and is composed of sediments belonging 
to the Lower Marine stage, the Lower Freshwater stage, and 
the Upper Marine stage. Interbedded with the last-named 
are one or two thin flows of rhyolite and a certain 
amount of tuffaceous material, but the importance of this 
occurrence, compared with the other blocks, is very small. 
(iv.) Condamine Block—This is situated about the 
Condamine River, 14 miles south-east of Warwick. Inter- 
bedded with the Upper Marine sediments is a series of 
rhyolite tuffs about 700 feet thick. Conformably bedded 
beneath the tuffs are tuffaceous mudstones containing 
abundant remains of Trachypora Wilkinson, &., while 
above them are rhyolite grits containing Martiniopsis 
subradiata, Trachypora Wilkinsoni, Productus brachy- 
therus, &&., so that there is little doubt as to the Upper 
Marine age of the tuffs. . 
General Nature of the Activity, &e. 
Rhyolitic and dacitie effusions much preponderate, and 
with the exception of the Eight Mile Block there is little 
other than Rhyolite flows and tuffs. The fossils associated 
with the effusions are those characteristic of either the 
Upper Marine Stage or the Upper Freshwater Stage, but 
all are of the shallow water type. 
Probably the lowest portions of the Eight Mile Block 
and the Tunnel Block material were laid down in a shallow 
sea, but the great bulk of the volcanic material appears to 
have been extruded under terrestial conditions. At the 
Condamine and Stanthorpe Road Blocks, however, all the 
tuffaceous material appears to have been laid down as 
shallow marine deposits. 
The rhyolitic and dacitic effusions were mterrupted by 
extensive explosive phases, and in the Eight Mile Block the 
Eight Mile Range is composed almost entirely of dacite 
flows and tuffs, while the Rhyolite Range is made up of 
rivolite flows ana tuffs. 
Much of the rhyolite was very viscous, as it frequently 
shows well-developed fiuxion structure. 
