1872.] 



DAINTREE GEOLOGY OF QUEENSLAND. 



291 



or old river- course. Though of course this is an error soon discoveredj 

 I have been informed that they have often found gold under such 



Fig. 13. — Limestone Earner, BroTcen River, Northern Queensland. 



conditions ; if so, it would be a very valuable addition to our know- 

 ledge of the earliest period at wjiich auriferous quartz veins were 

 formed. 



On the track from the Broken Eiver to the Gilbert Diggings, 

 Devonian rocks several thousand feet thick may be observed, as they 

 are continuous in dip, without being repeated, for at least five miles 

 across the strike, with an average inclination of 60°. 



Although on the Broken Eiver and its tributaries a breadth of 

 thirty miles, with a length of sixty miles, is occupied by a persistent 

 outcrop of Devonian strata, gold has only been discovered in remu- 

 nerative quantities in a small gully, heading from a leading ridge, 

 where a trap dyke has penetrated the Palaeozoic rocks of the district. 



The following districts, however, where Devonian rocks prevail, 

 have been centres of gold-mining enterprise : — 



Lucky Yalley. 



Talgai. 



Gympie. 



Calliope. 



Boyne. 



Morinish. 

 Rosewood. 

 Mount Wyatt. 

 Broken River. 

 Portion of Gilbert. 



In every case here cited the country is traversed by trap-rocks of 

 a peculiar character, either diorite, diabase, or porphyrite ; and tufa- 

 oeous representatives of these are also found interstratified in the 



