114 IM^OCEEDINGS OF THE ROYAI. SOCIETY OF QUEENSLAND. 



Within the Northern Territory, on the massif itself, rocks 

 later than Cambrian show little sign of folding. Even the 

 Cambrian deposits in the Territory are often quite undisturbed 

 {see " Northern Territory Bulletin " 14). 



A Cambrian transgression formed limestones over a large 

 area from Hall's Creek in Western Australia to Camooweal in 

 Queensland. The fossils Olenellus Hardmanni and SalfereUa 

 Forresti are indicative of the age of the horizon. A later Permo- 

 Carboniferous inroad of the sea covered most of this area with 

 shales and sandstones. Mr. H. Y. L. Brown has satisfactorily 

 established the age of these beds by the help of fossils obtained 

 at Anson Bay, Port Keats, and Borroloola. A Cretaco- 

 Tertiary transgression or a series of oscillations in the late 

 Cretaceous and early Tertiary period led to the formation of 

 porcellanitic sandstones in numerous places, chiefly in the 

 coastal belt, with fossil remains of belemnites, ammonites, 

 gastropods, crayfish, &c. How far inland these late trans- 

 gressions extended is not clear, owing to the horizontality of 

 the Permo- Carboniferous rocks. The table sandstones of the 

 interior have been regarded by Tenison-Woods as Desert. 

 Sandstone, but imtil some joalseontological evidence can be found 

 I think it is safer to regard them as Permo -Carboniferous. 



The large area of Devonian rocks — the Burdekin series^ — 

 which we see Avcst of Townsville, probably occurs under the 

 Basalts and Cretaceous beds from Lyndhurst to Boulia, and 

 should bo picked up between Urandangi and Boulia, from 

 which region they most likely extend to the McDonnell Ranges, 

 though covered at intervals by Cretaceous and Tertiary beds. 

 In this belt the rocks overlying the Devonian would not be 

 greatly folded. 



From the Eungella goldfield, via the Sellheim field, west- 

 ward through the Cape River district, until the series disappears . 

 under the Cretaceous, we have a festoon in which folding 

 succeeded Permian sedimentation. 



Thus as we proceed from Georgetown south-east towards 

 Mackay, folding becomes progressively more recent, and when 

 one gets south of latitude 21 deg. south, the rocks assume more 

 and more the axial direction of the Cordilleran belt. 



Movements in the Cambrian massif have been entirely of 

 the plateau type, consisting of uplifts followed by long periods 



