128 VOLCANIC ROCKS OF SOUTH-EASTERN QUEENSLAND 



less in int<'rpreting it as a sill than as an interbedded flow. 

 The material is very much weathered and is probably a sill 

 connected with the trachytic mass at Mount Flinders. 



The evidence put forward by Wearne "° for a Trias- 

 Jura age for some of the volcanic rocks is here summarised 

 and is as follows : — 



(1) Occurrence of waterworn volcanic pebbles in 

 beds of conglomerate, near the top of the 

 Walloon series. These pebbles have been found 

 near Mount Flinders, near Mount Alford, in 

 Blenheim Creek and near Esk. 



(2) Occurrence of a piece of volcanic tuff contain- 

 ing imprints of Trias-Jura plants and associated 

 with basalts at the Hip Roof Range, south of 

 Laidley. 



(3) Occurrence near Esk of volcanic tuff contain- 

 ing imprints of Trias- Jura plants. 



(4) Interbedded alkaline trachyte with shales con- 

 taining fossil plants of Mesozoic age, 5 miles 

 north of Esk. 



With respect to (1) the author has carefully examined 

 many similar conglomerate beds, and most of those men- 

 tioned by Wearne, and there is no doubt about the presence 

 of trach3d;ic, rhyolitie and basic-porphyry waterworn 

 pebbles in these beds which are apparently of Walloon age. 

 The pebbles, however, are not quite comparable with the 

 trachytes and rhyolites which have been described as vol- 

 canic lavas &c., but they are indistinguishable from the 

 rhyolitie and trachytic material which occurs as intrusive 

 dykes through the Palaeozoic rocks of this area. These dykes 

 are particularly well seen in the Taylor Range area, and 

 have been described by Bryan.-^ There is no doubt that 

 these dyke rocks, which represent the hypabyssal nhase 

 following the deep-seated intrusions of grano-diorite 

 material occurring along the D'Aguilar Range, are older 

 thaii the Trias-Jura sediments, as one never finds the intru- 



' Proc. Eoy. Soc, N.S.W., xlv. ; A.A.A.S., xiv., Melbourne, 1913. 

 Proc. Roy. Soc, Q'land, xxvi. (1914). 



