New South Wales. 
19 
however, to remark that Professor M‘Coy does not adopt this 
determination, considering the rocks to be younger.* 
"Whatever he the age of the Gympie beds, in rocks of apparently 
the same age in Queensland there is a vast amount of mineral 
* The following arc the grounds upon which I ventured an opinion as to 
their Carboniferous age in 1871 (“j Progress of Gold Discovery from I860 
to 1871,” pp. 5-7) : — 
Kotos on Mr. Racket's Collection of Rocks and Fossils from the Gympie 
Gold-field. 
L. This collection comprises two series of rocks, the one Sedimentary, the 
other intrusive. 
2. The latter consists of varieties of the greenstone group of the Plutonic 
formations. 
«5. The former embraces several kinds of rock. Among them are some so 
completely free from transmutation as to exhibit the characters of ordinary 
schift, sandstone, and breccia; others appear to have been derived from 
volcanic asb of the dioritie type, and have been, since their deposit, altered 
by intrusive agency so as to put on the resemblance of diorite or greenstone, 
and as such they have by some been classified. 
4. The presence of fossils serves, however, to illustrate their conditions as 
ash-beds deposited in an ocean troubled by contemporaneous or subsequent 
igneous action, which, after the consolidation (in part) of the strata containing 
organic bodies, became changed by the new eruption. A considerable portion 
of the Gympie Gold-field has thus become a metamorphie area. 
5. Such phenomena are by no means rare in Australia. Bedded, as well as 
intersecting, basalt occurs largely in the lllawarra Carboniferous district of 
Ncvy South Wales, whilst, in the western border of that Colony (as about 
Wellington) greenstone is exhibited in a similar connection with Upper 
Silurian Strata. At Waimalee (Prospect Hill, near Parramatta) an old diorite, 
precisely like that of Bople, to the eastward of the Mary River, has furnished 
a matrix for the plant beds of the Wiananmtta Rocks, the highest in the New 
South Wales scries of Sedimentary deposits ; and these have been subsequently 
transmuted by younger igneous rocks that pierce and overflow them. 
(I. The whole of the Sedimentary deposits in Mr. Racket's collection betray 
the effects of contemporaneous independent forces. The purple schistose rock 
contains, besides an occasional fossil, fragments of igneous prodm ts, and some 
segregated quartz; mul the gray and greenish fine-grained stone, derived from 
dioritie detritus, contains frequently much lime, many imperfect squeezed 
fossils, with a portion of some drifted matter. Patches of the purple schist- 
occur in the green rock ; and in the brecciated beds composed of fragmentary 
materials (the result of violence and subsequent consolidation in a state of 
repose), chemical action has produced segregations of quartz which simulate true 
quartz veins. 
7. It is to be presumed that the fissures in the strata which are now filled 
in with auriferous and cupriferous quartz were formed at a later period. A 
considerable time must have elapsed, for many of the fossils are themselves 
changed or partly obliterated, and arc traceable only by the glistening cleavage 
of calcareous sections.' 
8. Mr. Hacket has marked one variety of rock Schalstcin, and it certainly 
agrees with the definition of that species, inasmuch as it is laminated with 
thin partings or coatings of calc-spar. Now this is a very common occurrence 
in parts of Germany where greenstone is also present, and where the age of 
the rocks is Devonian. Schalstcin is truly a derivative and not an inde¬ 
pendent product, and therefore must be included with the other transmuted 
deposits. This rock exhibits at Gympie an exact resemblance to its namesake 
