82 



determination was made, and it seems more probable to conclude 

 that some Cambrian shell was found, and incorrectly referred to 

 Pentamerus oblongus than assume the hypothetical occurrence of 

 a set of beds which are not known to exist in any part of the 

 colony. 



Compared with Other Lower Cambrian Localities. 



The most Southerly extension of the Cambrian limestone 

 hitherto known in the colony is in the Curramulka District, 

 Yorke's Peninsula, in latitude a little North of Adelaide. The 

 outcrop, which is generally inconspicuous, can be traced at inter- 

 vals in a Northerly direction from Curramulka to Winulta 

 Creek, a distance of 35 miles. The beds in this area, except at 

 one locality, are but slightly disturbed, and when seen in section, 

 exhibit slight undulations, with a dip usually from 8° to 15°. 

 The exception referred to was observed by the present writer in 

 February last, when an anticlinal axis of some importance was 

 noted parallel with the coast a few miles South of Ardrossan. 

 The Eastern limbs of this anticline can be seen one and a-half 

 miles South of Rogue's Point, in a bold ridge of Ardrossan 

 marble, 20 feet thick, dipping 40° E., as the beds pass out of 

 sight below water level. We have thus the interesting fact that 

 Lower Cambrian beds occupy portions of the coast line on both 

 sides of Gulf St. Vincent, and the dip, respectively, is towards 

 the trough now occupied by this arm of the sea. 



Beds of Cambrian age have a great development in the Flinders 

 Ranges, north of Quorn, probably extending nearly 200 miles in 

 a north and south direction. Limestones with Archceocyathince 

 occur in these ranges at several localities, representing in their 

 extreme positions' a geographical line of about 100 miles. The 

 palaeontological contents of these beds, as well as those of Yorke's 

 Peninsula, have been elucidated by Prof. R. Tate* and Mr. R. 

 Etheridge, jun.,f but our knowledge of the stratigraphical 

 phenomena of the Archceocyathince marbles and their associated 

 beds of the Flinders Ranges is very imperfect. 



Geological Age of the Mount Lofty Ranges. 



It is impossible to ignore the important bearing of this latest 

 discovery of Lower Cambrian fossils on the geological age of the 

 Mount Lofty Ranges. The general uniformity of strike and dip 

 in the rocks throughout this extensive area has led to the opinion 

 held by many that the hill country of the Southern portions of 

 the province represents one great conformable series, and, on 

 various data, its geological position has been commonly referred 



* Trans. Roy. Soc, S. Aus., vol. XV. (1892), p. 183. 

 Ubid, vol. XIII. (1890), p. 10. 



