PHYSIOGRAPHY OF THE AUSTRALIAN ALPS. 383 



places, as at Butcher's Creek, pass into or alternate with subordi- 

 nate conglomerates, in which angular or rounded fragments of 

 sedimentary rocks are of common occurrence. The whole of the 

 Buchan beds have been ably described by Mr. Howitt. 



The rocks at Cowombat are nearly vertical, yellowish and 

 blue, thin shales, with bands of calcareous shale and limestone, 

 resting on the porphyries and altered Silurian rocks. The corals 

 and Brachipods found here are considered as younger than those 

 of the Bindi or Buchan beds, bwt still of Middle Devonian age. 



At the Native Dog Creek the beds consist of dark shales with 

 calcareous nodules and blue compact limestone. 



At Talboocabbera, junction of the Mitchell and Wentworth 

 Rivers, especially on Swamp Creek, there are limestone beds and 

 shales, containing Spirifera, Atryj^a, and other fossils similar to 

 Bindi. South-west from Talboocabbera are masses of slates, hard 

 shales, sandstones, and quartzites extending beyond Cobbamale to 

 Maximilian Creek, a tributary of the Avon River. The whole of 

 the rocks have been tilted, folded, compressed and metamorphosed. 



UPPER DEVONIAN. 



Between the Middle Devonian beds and the succeeding shales 

 intercalated with thesandstones and conglomerates of Iguana Creek 

 (a tributary of the Mitchell River south from Cobbamale Creek), in 

 which fossil plant impressions have heen discovered of an Upper 

 Devonian facies, there is considerable unconformability. At Iguana 

 Creek, the fossils include — Cordaites austrah's, Archceopteris 

 Hotcitti, and Sphenoptei'is ignanensis. A splendid section shewing 

 the sequence of the beds of conglomerate, sandstones, f el sites, 

 shales, vesicular basalt, mudstones, quartz grits, etc., of the Upper 

 Devonian series at Snowy Blufl' is given in Mr. Howitt's, " Notes 

 on the Devonian Rocks of North Gippsland."* 



The stx-atigraphical unconformability between the Lower and 

 Upper Devonian groups would, I think, indicate an emergence of 

 the land, and extensive and long continued denudation, probably 

 littoral and sub-aerial, of the JNIiddle Devonian beds subsequent to 

 their plication, prior to the submergence of the sui-face and the 

 deposition of the Upper Devonian series. There are not wanting 

 evidences of such submergence to a depth of not less than 5,000 

 feet lower than it is now. Intrusive to the Devonian rocks are 

 masses of quartz porphyry forming characteristic outlines where 

 the sediments have been denuded. 



The absence of Mezozoic, or of Carbonaceous rocks, in the Aus- 

 tralian Alps, would I think, imply a continuous land surface 

 since Devonian times over that area. 



Between the Devonian and Miocene, there is a complete hiatus 

 in the Australian Alps. 



* Progress Report, Geol. Survey Victoria, No. 3. 



