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PROCEEDINGS OF SECTION C. 
As regards the general physical and geological features of the 
neighbourhood of Hallett’s Cove, it may be stated that the country 
is undulating and hilly at this spot, where a low spur from the Mount 
Lofty Range trends westerly to the sea coast, and so forms the 
boundary on the south of the Adelaide Plains. The latter consist of 
alluvial deposits of Recent and Pleistocene age, resting on Marine 
Tertiary beds. 
The spur consists of Arehiean strata of vast thickness, and 
terminates seawards in rocky cliffs from 50 to 100 feet in height. 
At Hallett’s Cove a terrace of Tertiary rock rises from 120 to 160 
feet above the sea. This extends inland for about one-quarter oil a 
mile in an east and west direction, and for over three-quarters of a mile 
north and south, its trend being approximately parallel with that of 
the coast. Almost co-extensive with the Tertiary strata are the 
Glacial Beds, both they and the Tertiaries reposing in a valley or 
trough of erosion in the Archaean rocks. Northwards the trough 
appears to end in a cul-de-sac. Its boundary on the south has not vet 
been accurately defined. Where the Glacial Beds have been recently 
denuded away, at the edge of the sea-cliffs, a striated pavement of 
Archaean rock is invariably exposed. This can be traced for about half 
a mile to the north of Black Point, and for about a mile and a-half to 
the south. Seawards its continuity has been interrupted by the shelf 
notched in it by the erosive action of the ocean ; but it is evident from 
the section to the south of Black Point that it continues below sea- 
level, the trough in the Archaean rock above referred to trending sea- 
wards, and its bottom lying below the level of low tide between Black 
Point and the mouth of the Field River. Although the strip of 
glaciated pavement, at present exposed, is only from a few feet to a 
few yards in width, it is evident that it would be found everywhere to 
underlie the Glacial Beds, and, therefore, to extend inland from the 
face of the cliffs for about a quarter of a mile. 
The geological formations represented at Halletb's Cove are 
briefly as follows : — 
(1.) Archaean ( Pre - Cambrian ). — The local rocks of this age consist 
of indurated purplish red clay shales with greenish bands, beds of hard 
gray quartzite, and occasional thin layers of siliceous limestone. 
At one spot in Hallett’s Cove the purple shales contain numerous 
pebbles of gneissic granite, black quartzite, &e. 
The bedding planes are regular and well marked, and occasionally, 
as at the quarry about five miles from Hallett’s Cove, on the road 
towards Adelaide, the Archaean rocks, consisting of micaceous mud- 
stones, are finely laminated. Cleavage and joints are developed in 
places, but not to such an extent as to obscure the bedding. 
For some distance to the north and south of Black Point a well- 
marked anticlinal axis runs through the Archaean rocks, its trend being 
S. 21° W., and northwards it bends to N. 31° E. The prevalent dip of 
the Archseans is AY. 10° to 20° N., at from 40° to 78°. 
AYhercver their surface has been freshly exposed, through the 
removal by denudation of the overlying Glacial Beds, the Archaean 
rocks are seen to have been strongly glaciated, the rocks having been 
ground down, polished, striated, and grooved. The general trend of 
the grooves is nearly north and south, the southern end being the 
