CHAPTEE IV. 
MIDDLE DEVONIAlSr (BDEDEKIN EOEMATION). 
ARGENTINE SILVER FIELD. 
Eocks of Devouian age occur in at least five localities in Queensland — viz., the 
Burdekin Vallejo, including the Broken and Eanniug Eivers, the mountains north of the 
Eeid Eiver crossed by the Northern Eailway, Clermont Central Eailway, and Hunter 
and Marble Islands in the Northumbeidand Hroup. 
It is possible and even probable that considerable areas coloured as schists, 
slates, &c., of undetermined age may yet be recognised as belonging to the Devonian, 
but for the present the localities above named are the only ones in which the presence 
of Devonian rocks h.as been determined upon sufficient evidence. The Eev. W. B. * 
Clarke attributed a Silurian age to the slates, quartzites, &c., which cross the border of 
New South Wales into Queensland at the heads of the Severn Eiver. 
Apliii, in his “Eeport on the Upper Condamine,”* speaks of the Silurian rocks 
extending connectedly along the southern border, but remarks on the fossils that “ in 
general asjmct they resemble the fossils of the diorite slates at Gympie” (page 5). He 
mentions only Froductus and Spirifer, as occurring at Elbow Creek, Lucky Valley, 
together with crinoids and corals. To his statement regarding the resemblance of the 
fossils to those of Gympie, I attach greater weight than to his determination of two 
genera of Brachiopods which range up to a much later date than Silurian. Daintree 
(1872) appears to have regarded the greater part of tlie stratified rocks occurring in 
the eastern ranges of the Colony, with the exception of the Coal Measures, as Devonianf ; 
and Mr. E. Etheridge, E.E.S., in his Appendix to Daiutree’s Paper, massed the fossils 
from the Gympie Beds with those from the Burdekin Beds as Devonian J — a classi- 
fication which later collections have showm to be untenable. 
Gregory, in his “ Geological Map of Mo reton and Darling Downs (1879) ,” coloured 
the altered slates and sandstones extending from near the border northw'ard to near 
Brisbane, and again from Brisbane to the heads of the Caboolturc, as Devonian, and in 
his Eeport on the Geological Eeatiires of the South-eastern Districts of the Colony § 
describes them as such, and refers to the Gympie Beds as of the same age. 
In my Geological Map, prepared for the Colonial and Indian Exhibition of 188G, 
I coloured the strata in the neighbourhood of Gympie as Lower Carboniferous, but had 
not yet seen any reason for disagreeing with Daintree’s conclusions as to the Devonian 
age of the remainder of the altered stratified rocks which extend, with some interrup- 
tions, from Ecppcl Bay to the southern border. In my “ Handbook of Queensland 
Geology” (Brisbane, 1880), I said (p. 23): — “ It is with considerable hesitation that I 
class, in the meantime, the greater part of the Palaeozoic rocks south of Marlborough 
as belonging to the Burdekin Beds. It is quite likely that among the highly inclined 
and much distributed rocks of this region strata will yet be found separable, on account 
of their fossil contents and their stratigraphical relations, from the rest, and of 
different ages. But fossiliferous limestones, apparently identical with the Burdekin 
* Biisbiine : by Authority : 18G9. 
t CJiuart. Journ. Gool. Soc., vol. xxviii., p. 28S. 
J Lor., rit, p. 325. 
§ Brisbane : by Authority : 1879, p. 7. 
