50 GEOLOGY OF LOWER MESOZOIC ROCKS OF QUEENSLAND, 



spread distribution of a fine-grained, ferruginous sandstone. 

 This rock is very characteristic, and is developed on one or 

 perhaps more horizons. It has been observed from the following 

 localities : Beaudesert, Kalbar(late Engelsburg), near Warwick, 

 near Toowoomba, three miles north of Texas, a number of 

 localities in the Wallumbilla-Roma district, and Stewart's 

 Creek, Rockhampton. All these occurrences are in the Walloon 

 Series or its equivalents. This rock, in nearly every case, 

 contains fossil plants, the genus Otozamites being particularly 

 characteristic. It is also to be noted that, in the Jurassic 

 rocks of Western Australia, Otozamites occurs in a fine-grained, 

 ferruginous sandstone. 



The widespread distribution of this rock, apparently on a few 

 horizons, leads us to believe that it gives indication of some 

 special conditions of deposition. It would, however, be useless 

 to attempt to account adequately for it in the present state of , 

 our knowledge of the conditions under which these beds were 

 laid down; most of the areas from which it has been obtained 

 have not yet been studied in detail geologically. 



{d) Coals. — The development of a number of coal-seams of 

 workable quality and thickness is an important feature of the 

 Lower Mesozoic rocks of Queensland. Coal is obtained from 

 both the Ipswich and Walloon Series, and the character of the 

 coal from the two Series is generally distinct. This distinction 

 has been expressed both by Mr. Cameron and Mr. Marks. The 

 former, speaking of the Walloon coals, says* "the coals hitherto 

 found show characteristic conchoidal fracture in the hand-speci- 

 men, burn readily with a long, luminous flame, and give off a 

 much larger proportion of volatile hydrocarbons when heated in 

 a closed vessel than do the brittle, bituminous coals of the 

 Ipswich Beds." 



On the same subject, Marks saysf "The Walloon Beds are 

 characterised by coals which, like those of the Darling Downs, 

 are of the nature of a cannel coal — highly gaseous, hard, and 



* Queensland Geol, Sufv., Publication No.204, p. 16. 

 t Queensland Geol. Surv., Publication No. 225, p. 9. 



