PRESIDENTIAL ADDRESS. 43 



Enclosed between these two old belts of Silurian or Pre- 

 Silurian rock is the northern end of the great coal-basin of 

 Queensland. This extends to near the head of the Dawson 

 River. Its main axis strikes about N. 27° W. (true). The 

 long axes of the intrusive masses of granite follow approxi- 

 mately parallel directions, as do the folds in the Gympie 

 rocks. 



At its north end the Bowen Goal Basin is abruptly 

 rounded off by an immense bar of granite trending nearly 

 due E. and W. (true). At Peak Downs the folds have a 

 general north-easterly to south-westerly trend. At the 

 Cape and Charters Towers the trend of the folding in rocks 

 of Pre-Burdekin (Pre-Devonian) age is about W.N.W. and 

 E.S.E.. W. H. Rands 1 estimates that the schists and 

 quartzites of the Gape River Gold Field may have a thick- 

 ness, without allowing for possible repetition of beds, of 

 from five and a half to six miles, they dip at 30 - 35° towards 

 S.S.W. At Ohillagoe the folds strike about E.S.E.. In 

 the Middle Devonian rocks of the Burdekin Basin the folds 

 trend about N. 40° E. and S. 40° W. Dr. R. L. Jack, in 

 1894, wrote to me " There is no evidence as to when this 

 folding took place in Queensland as the Devonian is not 

 seen anywhere in contact with newer rocks, and so we 

 cannot tell whether they have been folded together or not. 

 The hiatus, however, between middle Devonian and our 

 next series (Gympie) itself implies an upheaval and in ail 

 probability a folding prior to Gympie," (i.e. Carboniferous 

 times.— T.W.E.D.) 



It is worthy of note that these Burdekin folds trend at 

 right angles to the adjacent coast line. In the Gilbert 

 Gold-field, still further north, there are two well marked 

 sets of folds, trending respectively E.S.E. to W.N.W., and 



1 On the Cape River Grold Field. By authority Brisbane, 1868. 



