88 
PROCEEDINGS OF THE ROYAL SOCIETY OF QUEENSLAND. 
or both. The latest formations in the Arnnta complex, within the Hart’s 
Range, lying in a few places unconformably on the gneiss series, consist 
of quartzites, slates and schists. There is reason to believe that this 
formation is composed of remnants of the Perta-knurra series. 
North of the Plenty River and fringing the boundary of the Arunta 
Complex there are areas and ranges built up of schists, quartzites and 
arkoses and slates, highly inclined and often vertically bedded. These 
belong to the Perta-knurra Series of Madigan. They were strongly 
folded up against the older massif of Aruntan rocks. The same series 
is noted in the Anningie Ranges west of Barrow Creek, consisting here 
of hematite-mica-schist, and quartzite. This series ( Madigan ’s Perta- 
knurra) is probably identical with the Mosquito Creek Series recorded 
in other parts of the Territory and Western Australia. 
Both the Arunta Complex and the rocks of the Perta-Knurra Series 
are traversed by abundant amphibolite and pegmatite dykes. The later 
series are not affected by them. It is therefore obvious that at the end 
of the Pertaknurra (or Mosquito Creek) period there were great igneous 
intrusions accompanying the folding of the rocks of that period. In the 
Anningie area pegmatitic and gabbroic amphibolite dykes appear as 
complementary dykes. Outcrops of granite of this period show up in the 
Huckitta area and Tower Rock area north of the Plenty River. 
It would take too much space to recapitulate Madigan ’s work in 
the Macdonnells. It is sufficient to remark that the formations north 
of the Hart’s and Strangway Ranges are, with minor modifications, 
much the same as those south of the Macdonnell Ranges. 
The Plenty River rises in the western portion of the Hart’s Range 
and sweeps in an arc about 10 to 20 miles north of that range easterly 
and then south past the east end of the Hart’s Range towards the 
Simpson Desert. Both south and north of the east-flowing part of this 
river there are table hills taken to be residuals of the Cambrian. These 
hills show only low dips. North of the Plenty River the Arunta 
Complex is frequently fringed by the Pertaknurra or Mosquito Creek 
Series, steeply dipping and highly metamorphosed quartzites and 
hematite and mica schists. Overlapping these, and only low-dipping, 
there is an extensive series of quartzites with some rhyolitic and basaltic 
rocks interbedded, but containing no quartz reefs or pegmatite dykes. 
There are fault zones in these with the fault breccia chalcedonie. Over- 
lying these and dipping at similar low angles and seemingly conformable 
to the previous there are extensive areas of quartzite and limestone 
which are regarded as Cambrian, as Cambrian fossils have been 
obtained in them in places. The conformable fiat series under the 
Cambrian has been regarded as the Pertatataka by Madigan, and the 
occurrence of volcanic rocks in the series brings about a close similarity 
to the Nullagine. 
