228 



merge into the next following. Typically developed at Brigh- 

 ton, Reynella, and Hackham. 



(c) Fine-grained and banded clay slates (ribbon slate), 

 which are slightly calcareous. At Tapley's Hill, etc. 



In continuation of the same subject, the present paper 

 deals with the beds v-hich follow in descending order, and are 

 locally developed in the foot-hills and main elevations of the 

 Mount Lofty Ranges. This carries the investigations (so far 

 as a generalized description goes), of the Cambrian succes- 

 sion down to the basal beds. 



The ground covered in the present paper is so extensive, 

 and involves so many jDoints of interest, that only a mere 

 outline of the facts can be dealt with, leaving for future 

 efforts a more detailed description of the several members of 

 the series. 



The greatly disturbed condition of the beds within the 

 area presents many points of difficulty to the field geologist. 

 The continuity of the beds is frequently broken by folding, 

 over-folding, and faulting, and in a series such as now dealt 

 with (where there is little to distinguish individual beds of 

 the same class from each other) it becomes a most difficult 

 task to determine the true order of succession. To fill in the 

 outline will require detailed and prolonged investigations in 

 the field. 



II. — ^Cambrian Glacial Till, 



In April, 1901, a ''Preliminary Note" was read before 

 this Society, submitting definite evidences of the glacial origin 

 of a thick set of beds in our Cambrian series, covering a very 

 wide area in South Australia. Previous observers have in 

 one form or another, noted the existence of these beds, and in 

 the following references I include all such as are known to 

 me. 



1859. A. R. C. Selwvn. ''June 1. Ascended Mount 

 Bryan [Razorback, north of the Burra], and found it com- 

 posed almost entirely of an olive-green and brown schist, or 

 'shaal stein' breccia or conglomerate, . . . associated with 

 the above, on the east flank of the hill, are bands of hard 

 quartzose rock, occasionally with a laminat-ed or gneissose 

 structure ; and near the base of the hill on the same side there 

 appears to be a thin band or dyke of hornblendic 

 granite, numerous fragments of which are scattered about on 

 the surface, though I could not find any in situ." Pari. 

 Paper No. 20 of 1859, p. 8. [The granites observed by Sel- 

 wyn occur as glacial erratics.]. 



