264 
Although frequently looked for, no fossil remains have 
been found in these limestones except a few casts of Radio- 
laria. This is the more remarkable as the limestones have 
been, as a rule, but little altered under metamorphic action. 
The fossiliferous pebble found on the coast, near Brighton, 
referred to above, has apparently come from a limestone 
slightly higher in the series, and belongs to the purple slates 
division. Descriptions of the Radiolara observed, and fuller 
remarks on the Brighton section, will be found in a “Note on 
the Occurrence of Casts of Radiolaria in Pre-Cambrian (?) 
Rocks of South Australia.” (Proc. Linn. Soc. N.S.W., 
1896, p. 571.) The paper containing these descriptions was 
written under the prevailing view, held at that time, that 
the western flanks of the Mount Lofty Ranges were probably 
of Pre-Cambrian age. 
(C) Tapley's Hill Clay Slates. 
Tapley's Hill is on the Main South Road, about eight miles 
from Adelaide, and due east from Brighton. The so-called 
“hill” is, in reality, the escarpment of the older rocks, which, 
in a curve to seawards, determine the southern limits of the 
Adelaide Plains. From the summit of Tapley's Hill a coastal 
plateau stretches southwards to the Onkaparinga. 
The hillside is marked by numerous quarries, and the 
Stone won is extensively used in Adelaide for kerbing and 
building. It is a very fine-grained, homogeneous stone, which 
cleaves easily at a high augle to the bedding planes. This 
cleavage, associated with cubical jointing, makes it a free- 
working quarry stone. The bedding plane, or grain of the 
Stone, is marked by a banded structure, which, from carry- 
ing a protoxide of iron, becomes strongly dsveloped in 
weathered faces, giving it the character of a "ribbon" slate. 
This banded structure is a very constant and characteristic 
feature, and is usually sufficient to determine the horizon 
when these beds are met with in distant localities. 
The lithologcal type of this division is remarkably uniform. 
It is incapable of subdivision, as it practically consists of a 
single bed of great thickness. Although seen in many places 
I have not in a single instance detected a quartzite or aren- 
aceous band throughout its vertical extent. The beds are 
often sub-calcareous, and, by a process of leaching, produce a 
superficial travertine deposit, which fills in the crevices and 
cements the fragments of shale which form the outerops. 
There is no well-defined limit between these clay slates and 
the calcareous series which immediately overlie them. The 
upper parts of the Tapley's Hill beds become more calcareous 
whilst preserving their banded structure, and pass conform- 
ably up into the siliceous limestones of the member above. 
