186 PROCEEDINGS OF SECTION C. 



one sees these same freshwater sandstones and shales very much 

 puckered and folded, also faulted to some extent. 



The shape and existence of this headland is dependent on the fold- 

 ing to which these rocks have been subjected, and a small bay conforms 

 exactly with a synclinal fold in the strata as shown up in plan on the 

 shore. 



At low tide there is a magnificent section exposed all around 

 Point Vernon, and a strike fault whose plane lies in a direction 30° W. 

 of N. and 30° E. of S. is seen here, but the amount of displacement 

 could net be determined. 



Faulting. 



The most extensive fault in the area is the one on Point Vernon, 

 but it appears to be rather of local importance and. not to be of any great 

 extent. On Woody Island there are a few minor dip faults, of no 

 importance, however. 



Igneous Rocks. 



There is a marked absence of dykes or any traces of igneous rocks 

 throughout the area. 



General Summary and Conclusions. 



The existence and characteristic shape of these islands are clearly 

 dependent on the structural features and lithological characters of the 

 rocks forming them. 



The Burram formation does not extend, as at present mapped, 

 ail over this area, for marine beds of Lower Cretaceous (Rolling Dov/ns) 

 age occur on Woody Island, Duck Islands, Picnic Island, Little Woody 

 Island, and a rocky patch S.E. of Little Woody Island and just off 

 Fraser Island. 



Interbedded with these marine Lower Cretaceous rocks, and also 

 conformably overlying them, are freshwater sandstones and shales 

 containing abundant unrecognizable plant remains. On Woody 

 Island two seams of brown shaley coal occur. 



The interbedded freshwater beds, and also the overlying ones, 

 must be of Lower Cretaceous age, and not of Trias-Jura age as pre- 

 viously believed. 



During the deposition of the sediments forming these beds there 

 must have been at least two gradual movements of elevation alter- 

 nated by two gradual depressions followed by a long period of elevation 

 in which the main series of freshwater beds were deposited. 



Some time subsequent to the longer period of elevation the area 

 has been subjected to earth-movements resulting in the formation 

 of anticlines and synclines whose axes have a N.W. and S.E. tread. 



