CARBONIFEROUS AND PERMO-CARBONIFEROUS ROCKS, N.S.W. 319 



than to sparsely represented older forms. Provisionally 

 one might perhaps sum up as follows: — 



An Upper Carboniferous, probably Uralian age, can be 

 assumed for the tillite beds of the western coastal areas of 

 West Australia, though not necessarily for all the overlying 

 marine and Glossopteris beds. This age, for the tillites at 

 any rate, is in accordance with the classification at present 

 adopted by the Government Geologist of West Australia, 

 Mr. A. Gibb Maitland. At the same time it may be pointed 

 out that until it has been found possible to do some zoning 

 work on the fossils of the Irwin, Gascoyne, Kimberley and 

 Northern Territory regions, it is unsafe to form any but 

 very tentative conclusions. 1 



Obviously if the tillites of the Irwin are Carboniferous 

 in age they are not as old as the Burindi Series, and the 

 large number of marine species common to the Productus 

 limestone of the Salt Range, associated with the Irwin 

 Beds makes it probable that they are distinctly newer 

 than the basal Rhacopteris-bearing part of the Kuttung 

 Series (Middle Carboniferous) of New South Wales. There 

 is little doubt that the tillite beds of the Irwin River are 

 (tested by the New South Wales standard) pre-Greta in age, 

 i.e. Post-Rhacopteris and Pre-Greta, belonging therefore 

 (a) either to the small glacial horizon of the Eurydesma 

 Beds 2400 feet above the top tillite of the Kuttung of New 

 South Wales, or (b) to transition beds between the top 

 tillites of the Kuttung and the basal beds of the Lower 

 Marine Series, or (c) (and this seems quite possible) to the 

 horizon of the top tillite of the Kuttung. Further it is 

 quite possible that the whole of the marine strata in the 

 Irwin area, that is, the Pre-Greta strata — may be Uralian. 

 On this evidence it may be suggested that in the type 

 district for the Permo-Oarboniferous sequence in New South 

 Wales — the Lower Hunter region near Maitland — all that 



1 Dr. W. G. Woolnough is now surveying the Irwin region and will 

 probably contribute a paper on it to this journal, shortly. 



