BY A. B. WALKOM. 



49 



some of the South-east Queensland volcanic rocks^ hut l)i-. 

 Richards has recently examined all their evidence* and shown 

 that, in each case, there is no doubt that the volcanic rocks are 

 of Cainozoic age. Since then, Mr. Dunstan lias placed the 

 volcanic rocks of the Glasshouse Mountains in the (?)Walloon 

 Series;! the only field-evidence regarding the age of these rocks 

 is that tliey are intrusive through a series of sandstones, which 

 Mr. Dunstan believed, at the time, to belong to the Ipswicli 

 Series. On the evidence of the relationship between these vol- 

 canic rocks and other volcanic rocks of South-eastein Queensland, 

 their age certainly seems to be Cainozoic. Some of the beds of 

 the Ipswich Series at Denmark Hill, Ipswicli, are regarded by 

 Mr. Dunstan as tufi'aceous in character. | 



The Bundamba Series, which succeeds the Ipswich Series, 

 consists, for the most part, of massive sandstones. With the 

 exception of one coal-seam about 1 foot, 6 inches thick, known 

 as the West Moreton seam, they have proved unproductive of 

 coal; they are also practically barren of fossils, the only record 

 being of silicified wood. The basal portion of the Bundamba 

 Series lies about seventy feet above the top seam (Aberdare 

 seam) in the Ipswich Series, and consists of coarse grits and 

 conglomerates. 



The Walloon Series, lithologically, is of somewhat similar 

 nature to the Ipswich Series. In consists mainly of compara- 

 tively soft sandstones, with which are interbedded fine-grained 

 shales and coal-seams. Conglomerates are developed, but are of 

 limited occurrence. The soft sandstones and shales weather 

 away rapidly, and, consequently, in many places, outcrops are few 

 and inconspicuous. 



In the Stewart's Creek (Stanwell) district, the Series includes 

 a hard, white, siliceous tuff in which abundant fossils are pre- 

 served. 



A remarkable feature in the Walloon Series is the verv wide- 



* For summary of evidence, see Proc. Roy. Soc. Queensland, xxvii. (2) 

 1916, p. 126. 



t Harrap's School Ueographj' of Qvieensland, Appendix B, p 16 

 X Queensland Geol. Suiv., Publication No.2o3, p.5 



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