74 
witli those of the Gympie Pormation, especially as similar slates containing corals and 
erinoid stems have proved to he quite characteristic of the Gympie Pormation, as 
developed in the Rockhampton District. 
Mr. A. C. Gregory, in his “ Report on the Geological Peatures of the isouth- 
eastern Districts of Queensland,”* refers to casts of Spirifer “ found in the Devonian 
slates and sandstones,” at Lucky Valley and the head of Rosenthal Creels, “ and also in 
the limestones and other beds of this series near Rockhampton.” 
Prom this meagre evidence, I regard the slates, &c., to the west and south of 
Warwick as belonging to the Gympie Pormation rather than to the Devonian. 
Mr. Aplin, in the report above quoted, frequently refers to the lithological 
resemblance of the slates, &c., of the Moretou Bay District, north of Brisbane, to the 
Gympie rocks, which, although he regarded them as Devonian, are now relegated to the 
Permo-Carboniferous. Abundant evidence will bo noted in the following pages in 
favour of transferring the greater part of the stratified rocks between this region and 
Rockhampton, from the Devonian to the Gympie Pormation. If these slates, &c., are 
of Permo-Carboniferous age, it is probable that so likewise are the slates, schists, and 
quartzites extending from Brisbane to the Border ; but in the meantime, in the absence 
of direct evidence, these are still left on the map as of “ undetermined age.” 
As in all probability the strata on the New South Wales side of the Border, 
provisionally mapped as “ Dpper Silurian or Silui’o-Devonian,” are continuous with 
those of Lucky Valley, we look to the work of New South Wales geologists in that 
region for light on the subject. Mr. (now Professor) T. W. Edgeworth David, in his 
exhaustive Memoir on the “ Geology of the Vegetable Creek Tin- Mining Pield,^ f in 
referring to some Polyzoa, Encrinites, Lamellibranchiata, and imivalvos found by him in 
the Parish of Arvid, confesse.s (p. 54) that “ these fossils prove the beds to be of marine 
origin, but do not afford conclusive evidence as to their age.” 
The Writer in 1886 made a partial survey of the Gympie Gold Pield, and a large 
collection of fossils. The Geological Survey Museum and the Queensland Museum 
both contain a considerable collection of fossils from the same locality. 
As my Colleague has carefully gone over the collections and the whole litera- 
ture of the PaloRontology of the Gympie Gold Pield, it is unnecessary for me to allude 
here further to the very puzzling lists of fossils furnished by early writers. The 
stratigraphical information also furnished by the Authors above referred to, although 
in many instances valuable, may be regarded as superseded, or added to and brought 
up to date, by the exhaustive Report of Mr. William H. Rands, “On the Gympie 
Gold Pield.” + 
The most important part of the Gympie Gold Pield {see Geological Map, PI. 48) 
is comprised within a strip of country on the northern bank of the Mary River, about 
two miles in length, with an average breadth of about three-quarters of a mile, extending 
from the town of Gympie southward to the Monkland. This area, it will be seen from 
the map, is bounded on the north, south, and west, by faults. “ This part of the field 
presents a series of alternations of different kinds of sedimentary strata with some 
intrusive igneous rocks, and also some of volcanic origin. Taking the average dip at 
22°, there must be somewhat over 2,000 feet in thickness of such strata. 
“The rocks of which these beds are composed consist chiefly of greywackes, 
altered sandstones, grey and black carbonaceous shales, grits, conglomerates, breccias, 
and limestone. Interbedded with these are amygdaloidal volcanic rocks and volcanic 
* Brisbane : by Authority : 1879, p. 7. 
t Mern. Geol. Survey N. S. Wales, Geology No. 1, 1887. Sydney ; Government Printer. 
J Brisbane ; by Authority : 1889. 
