REPORTS OF COMMITTEES. 265 



Hyolites, Oholella, &c. The glacial beds occur in tlie lower set of beds, 

 many thousands of feet below the limestones which carry characteristic 

 Cambrian types, and within a few thousands of feet of the basal beds 

 of the series, which rest, unconformably, on a Pre-Cambrian complex. 

 There is no apparent break in the order of succession throughout the 

 entire series. The geological horizon of the glacial beds is inferior to 

 the Archceocythince, and not much above the base of the Cambrian 

 series ; they can, therefore, be definitely classed as Lower Cambrian. 



2. Geographical Extent of the Beds. — Extended observations have 

 shown the enormous area affected by the glacial conditions in these 

 latitudes in Cambrian times. In the Mount Lofty Ranges near Ade- 

 laide the glacial beds only come to the surface in one great fold, with a 

 north and south strike. To the south the beds are lost sight of after 

 passing the Onkaparinga River — 20 miles south of Adelaide — beyond 

 which they are obscured by newer deposits, and are, moreover, cut 

 off by a great downthrow fault along the Willunga and Sellick's Hill 

 ranges, which brings in the Archceocyathince Umestones of the Upper 

 Cambrian. 



In the northern areas and throughout the Flinders Ranges the 

 glacial beds recur at intervals in great anticlinal and synclinal folds, 

 which take in the full width of the country from Mundallio Creek, near 

 Port Augusta, to the New South Wales border. On the eastern side 

 observations have been recently made by my colleague, Mr. Douglas 

 Mawson, B.Sc, which prove that the beds in question cross the borders 

 and are developed in the Barrier Ranges of New South Wales. 



In the northern FUnders they have been proved to outcrop in the 

 Mount Nor- West h and Willouran ranges c, on the north-west of 

 Hergott, as well as at the extreme north-eastern portion of the Flinders 

 Ranges to the north of Lake Frome.tZ The limits of their occurrence 

 have not been fixed either on the eastern or northern sides. The known 

 area of the Cambrian glacial beds, at present, is about 450 miles north 

 and south and 300 miles east and west. Their most northerly known 

 occurrence is in 29° 40' south latitude, which is within about 6° of the 

 Tropics. The glacial bed noted by Tate (Horn expedition), and subse- 

 quently by Spencer, at Yellow Cliff, on the River Finke, will probably 

 be found to be referable either directly to the Cambrian series or the 

 re-arrangement of the Cambrian glacial erratics in a deposit of later 

 date. The last-named supposition would explain the presence of desert 

 sandstone pebbles in the debris, as determined by Professor Tate, e as 

 well as the large granite boulders in Cunningham Gap, also in the Finke 



h Brown. — Report on Country East and West of Farina, Pari. Paper, No. 102 

 of 1884. 



c Howchin.— Trans. Roy. Soc, vol. XXX., 1906, p. 330. 



d Woodward. — Report on Range to the East of Farina, Pari., Paper, No. 40 

 of 1884. The present writer traced these beds for 50 miles through the 

 north-east Flinders as far as the Daly and Stanley mines, near the Freeling 

 Heights, where several well-marked glaciated stones were picked out 

 of the till. 



e Trans. Roy. Soc., S. Aus., vol .XXL, 1897, p. 68. 



