100 GEOLOGY OF LOWER MESOZOIC ROCKS OF QUEENSLAND, 



Our studies of the fossil floras indicate that the Ipswich Series 

 in Queensland was laid down at the same time as the Wiana- 

 matta Stage in New South Wales. The strata of this Series 

 were laid down over a comparatively restricted area in Southern 

 Queensland, though it is not possible to obtain an accurate idea 

 of its exact extent. Parts of the areas bordering the basin in 

 which the Ipswich Series was deposited were probably very 

 elevated, e.g., the Stanthorpe-Warwick, and the Gynipie Dis- 

 tricts, the extent of the elevation having been due to the exten- 

 sive intrusions of granite at the close of the Palaiozoic era. 



It is probable, also, that part of the Lower Mesozoic sediments 

 of Tasmania was deposited contemporaneously with the Wiana- 

 matta Stage in New South Wales, and the Ipswich Series in 

 Queensland. 



The Bundamba Series, which follows the Ipswich Series in 

 Queensland, has no equivalents, so far as we know, in Kew South 

 Wales ; apparently, sedimentation in the main Hawkesbury 

 Basin came to a close with the end of the Wianamatta Stage. 

 Later sediments in that State were laid down to the north and 

 north west. 



In Queensland, the dominant movement from the beginning 

 of the Ipswich epoch was a subsidence. This movement was not 

 continuous; there were, at least, breaks represented by the base 

 of the Bundamba Series and of the Walloon Series, and there 

 may have been further breaks within the Series. At the time 

 of these breaks there was probably a cessation of sedimentation, 

 accompanied by a slight uplift before the downward movement 

 reasserted itself; the predominance of the downward movement 

 is proved by the ever-increasing area covered by the Lower 

 Mesozoic sediments until, towards the close of the Walloon 

 epoch, the greater part of Queensland was probably covered by 

 enormous stretches of fresh water. The portions of Queensland 

 which were not submerged during the Walloon epoch (Jurassic) 

 include the north-western corner of the State, an area in the 

 neighbourhood of Hungerford on the New South Wales border, 

 and probably areas to the east of the present Main Divide, which 

 had been considerably elevated as a result of movements accom- 



