73 



beyond question. The erratics of the coast show that the. 

 ice must have passed over a granitic country in which the 

 felspathic constituents of the rock greatly preponderated, 

 and the kaolinised features of the clay on some parts of this 

 coast may be caused by the waste produced by such a fel- 

 spathic bed rock. 



The beach in front of this line of outcrop is strewn with 

 erratics of all sizes — quartzites and granites being in greatest 

 numbers. One of these, a large tabular mass of coarse- 

 grained, pink-colored, porphyritic granite, lying between tide 

 marks, measured fully twenty feet in diameter. 



The Eocene beds are absent from this section. 



Port Moorowie is situated on the southern coast about ten 

 miles south-west of Yorketown, and about six miles west of 

 the glacial beds near Troubridge Hill, already described. 

 A good exposure of boulder clay, carrying numerous erratics, 

 extends for about a mile near the jetty, chiefly on its eastern 

 side. The beds as seen in section in the cliffs make a low 

 anticline with a maximum height of about 36 ft., exhibiting 

 the following order : — 



1. Recent — Travertine and calcareous marls ... ... 15 feet 



f Reddish clay, with pipeclay bands ... 10 " 



2. Pre-Tertiary) White to bluish clay, with dark-red 



( Glacial) — 1 patches and streaks, carrying erratics ; 



y thickness exposed above sea level ... 11 " 



The boulder clay of this section shows a general resemblance 

 to the beds of the same age observed on the coast further to 

 the east, and which have already been described. In the 

 westerly outcrops of the Troubridge Hill beds (as also at Port 

 Moorowie), the upper part of the clay, varying from six to ten 

 feet in thickness, is apparently marked off from the under- 

 lying clay by a bedding plane. I saw no stones in this upper 

 layer, the absence of which may raise some doubt as to its 

 glacial origin, although such negative evidence cannot be 

 taken as conclusive, as considerable bodies of un- 

 doubted glacial clay sometimes occur in South Australia 

 in which no erratics are visible. I have included the layer 

 m question provisionally in the glacial series, but further 

 observations may show that it consists of re-arranged material 

 from the underlying till bed, and belongs to a later period. 



Erratics of small to moderate size are common on the 

 l^each at Port Moorowie. At one mile east from the jetty 

 a boulder of grey granite, with large crystals of orthoclase 

 giving it a porpliyritic character, was observed, and measured 

 at seven feet by four feet. 



