78 ME. C. E. TILLEY OX THE CxEAXITE-GXEISSES [vol. Ixxvii, 



characteristic being a great thicknes?; of massive qnartzites. rocks 

 ■which form inconspicuous members of the Hutchison Series. 



[d) The Duttou Series. 



The TVarrow Series has been metamorphosed by a later extrusion 

 of gi'anites, developed in the hundred of AVarrow. These granites 

 are distinguished bv the development of abundant tourmaline in 

 their more acid differentiates. A zone of lit -par- lit injection 

 along the contact has resulted in the development of injection- 

 gneisses from the AVarro\v schists. 



The serial sequence given above is one of decreasing geological 

 antiquity, and the oldest group of rocks developed in the area is 

 thus of sedimentary origin. 



There can be but little doubt as to the Pre-Cambrian ao-e of the 

 Hutchison,. Flinders, and Warrow Series, but the inelusi(jn of the 

 Dutton Series within the Pre-Cambrian is tentative only, and with 

 an increasino- knowledge of the igneous history of South Australia 

 it may be relegated to the Lower Palaeozoic. 



III. The Flixdees Seeies. 



[a) Geographical Extent. 



The members of this series occupy the most extensive area of 

 any of the Pre-Cambrian groups of rocks in Southern Eyre Pen- 

 insula. In the south, they are developed in the hundreds of Flinders 

 and Sleaford. Starting from their westernmost exposm-e at the 

 lied Banks on the west coast of the hundred of Sleaford, they crop 

 out along the coastline in an easterly direction past Cape Wiles to 

 Sleaford Bay, where the members of the Hutchison Series intervene 

 in a half-mile section. The coasthne farther east consists of JRecent 

 calcareous sands until the Curta Rocks are reached, adjacent to 

 the coast of the hundred of Flinders, when the gneisses reappear. 

 They are well developed farther south on the fringe near West 

 Point and Cape Catastrophe, and form the eastern coast of the 

 hundred of Flinders. 



The coastline of the liundi-ed of Lincoln, as also Boston Island, 

 consists of these rocks, and they are particularly well exposed on 

 the shore-line at Kirton Point, Port Lincoln. The minor peninsula 

 of Point Boston is formed of these gneisses, as also the island of 

 Louth and the promontory of Bolingbroke in the hundred of Louth. 

 In the hundred of Hutchison, they crop out along the coast south 

 of Tumby Bay and at Cape Euler. 



The inland exposures of the gneisses are but few and isolated. 

 The prominent hills behind Memory Cove (hundi'cd of Flinders) 

 consist of these rocks, and in the hundred of Lincoln they are well 

 exposed in the monadnocks of Cobbler's Hill, Xorth Hill, and 

 Winter Hill, occupying also an area behind Port Lincoln itself. 



