SALIENT POINTS IN THE GEOLOGY OP QUEENSLAND. 199 



prevail. Of this region Daiiitree observed* that — " The entire 

 Devonian system, as developed in Queensland, could be easily 

 and satisfactorily mapped," " On the track from the Broken River 

 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 dip of 60°," meaning a thickness of at least 23,000 feet. 

 Two years ago, I had for the lirst tmie an opportunity of visiting 

 this locality, and found in descending order : — 



Feet. 

 Grey-white and yellow sandstone, with shales ... 5,280 



Shales 1,000 



Limestones, alternating with shales, sandstone, 

 and conglomerates, the calcareous beds 

 fossiliferous ... ... ... .. ... 10,712 



Conglomerates and slates ... ... ... 580 



Slates, altered grits, quartzites, siliceous sand- 

 stones and conglomerates ... ... ... 3,210 



20,782 

 The 10,712 feet of calcareous rocks are fossiliferous, and the 

 whole 20,782 feet apparently form an unbroken series. Regarding 

 the 10,712 feet as undoubtedly equivalent to, or homotaxical 

 with the Middle Devonian, the underlying beds may pass 

 downward into Lower Devonian or even Silurian. The only 

 thing that is certain is that they expi'ess some portion of the time 

 represented by the unconformability immediately beneath the 

 limestone at Burdekin Downs, the Fanning, and the Reid. How 

 much of that time they account for it is impossible at present to 

 say. They (the beds below the calcareous Devonian rocks) are 

 somewhat altered, and it is noteworthy that the shale beds are 

 highly contorted, while adjacent sandstones and conglomerates are 

 rigidly linear. 



Directly, and to all appearance conformably succeeding the 

 Fanning limestone, are what at one time I proposed to call the 

 Dotswood beds. These are grey, greenish, brown and white 

 sandstones, and green and red shales. One of the white sand- 

 stones has yielded a plant named Dicranopliylhun australicum, 

 by Sir J. William Dawson. Interbedded with the stratified rocks 

 are amygdaloidal porphyrites, which are cupriferous. Above the 

 Broken River limestone, it may be remembered, are at least 

 6,280 feet of shales and grey, white, and yellow sandstones. 

 These probably are the equivalents of the Dotswood beds. 



The Star formation consists of grey, green, and blue shales, 

 white sandstones, conglomerates and limestones. In the type 

 district these overlie unconformably the granites, gneisg 



♦Quart. Journ. Geol. Soc, 1878, XXVIII., p. 290. X\j^J - -^.^f- / 



Li« R A ft Y :x 



