BY A. B. WALKOM. 61 



of the supposed fault at Heminant. The general directions of 

 the dip and of the axes of foldino- are shown in Plate ii. 



The extent of this folding, which has aftected both the Lower 

 Mesozoic rocks and the overlying Cretaceous strata, has not been 

 generally recognised, as may be seen from the following quota- 

 tions. Dr. Jensen* says, "Our Mesozoic sediments show no 

 folding of consequence. Generally speaking, they show only 

 slight dips, and have never been under the influence of tangential 

 pressure like the Mesozoic sediments of the Alps, Himalayas, 

 Java, etc "' Dr. Richards,! writing of South-eastern Queensland, 

 says, "Folding-movements of only a very gentle nature have 

 taken place since the Palseozoic era." 



Such statements are not consistent with the folding which 

 has been observed to the west of Ipswich, in the neighbourhood 

 of Hemmant; and in the Maryborough District, particularly on 

 \\oody Island, where the strata are often nearly vertical. 



The nature of the folding is illustrated in two Sections (Text- 

 fig. 1 ), of which Section A has been prepared from a section drawn 

 by Mr. Dunstan, and Section B from a combination of sections 

 by Messrs. Cameron and Marks. Neither Mr. Dunstan's nor 

 Mr. Cameron's original section has been published, and I am 

 indebted to them for permission to modify these sections for 

 use here. 



This folding may be quite adequately and reasonably explained 

 as the result of the adaptation of the earth's crust to a shrinking 

 nucleus. Such folding would, naturally, be expected along zones 

 of weakness, and the east coastal area of Australia is undoubt- 

 edly such a zone. Folding of this nature often passes into fault- 

 ing, and this may have occurred near Hemmant, where there 

 seems to be a line of faulting associated with folding, and also 

 in the Ipswich District, where, Mr. Cameron informs me, the 

 severe folding just south of Ipswich gives place to a fault further 

 north. 



From the originals of the sections, it was possible to Estimate, 

 approximately, the amount of shortening of the earth's crust 



* Proc. Roy. Soc. Queensland, xxiii., Pt.2, p. 163. 

 t Proc. Roy. Soc. Queensland, xxvii.,Pt.2, p. 114. 



