BY A. B. WALKOM. 63 



represented by the folding. Both sections are approximately at 

 right angles to the axes of folding. In the section between 

 Ipswich and the mouth of the Brisbane River, a shortening of 

 the order of 1|^ miles in .34 miles has been effected; and, in the 

 Maryborough district, a shortening of about 0*8 mile in 34 

 miles. This shortening is circumferential, and if it be regarded 

 as the shortening represented at this particular time for the 

 east-west extent of Australia (a not unreasonable supposition, 

 since we know of no other folding of the same age across Aus- 

 tralia), the radial shrinkage represented would be of the order 

 of 0-05%. 



Regarding the age of the folding, it certainly took place after 

 the Burrum Coal-Measures (probably Lower Cretaceous) were 

 deposited, for both Marine Cretaceous strata, which are ap- 

 parently conformable with the Tiaro Series, and the overlying 

 Burrum Coal-Measures have been subject to this folding force, 

 and have been folded to an extent closely comparable with the 

 Lower Mesozoic strata. This is shown by a comparison of 

 Sections A and B. 



This same folding took place before the Cainozoic, since it 

 has not affected any of the Cainozoic rocks of South eastern 

 Queensland. Also the disposition of the Cainozoic volcanic 

 rocks in South-eastern Queensland indicates that the Pre-Caino- 

 zoic drainage-system was approximately meridional, and this 

 may be closely connected with the N.30°W. strike of the folds 

 of the Lower Mesozoic rocks. 



In the Ipswich District, there appears to have been a sub- 

 sequent period of folding. This is comparatively restricted, and 

 the folds produced by it have an approximately meridional 

 direction. The Cainozoic deposits have been affected by this 

 movement, which must, therefore, have been later than the 

 period of folding already mentioned. I am indebted to Mr. 

 Cameron for information regarding this latter folding. 



Flora of the Lowek Mesozoic Rocks op Queensland. 

 The lists, presented below, of the Horas of the Ipswich and 

 Walloon Series have been prepared after a careful examination 



