251 



erii limits of these slates the local sandstones are seen again, 

 with a dip south-east at 45". These beds, with granitic in- 

 trusions, I regard as a Pre-Canibrian inlier that has become 

 exposed by the removal of the basal beds of the Cambrian 

 series. 



Another section of the beds in question can be seen on the 

 back road leading from Aldgate Station to Stirling. Jt is 

 almost due east of the one last described, and at no great dis- 

 tance from it. The outcrop is exposed in a small cutting 

 on the road, and shows unconformity between the two series 

 The Pre-Cambrian slates, with pegmatite veins, show folia, 

 with a dip south 10° west at 85°, and are overlain by hard 

 quartzite of the Mitcham type, which dips 10° east of south at 

 35^ 



A still more interesting exposure of the two unconform- 

 able series occurs about one and a half miles to the north- 

 east of the one just described, on Sections 1203, 1133. and 

 1134, Hundred of Onkaparinga. On the district road, in 

 front of Mr. Melrose's house, and on the creek to the east 

 of the road, an excellent line of junction can be studied. 

 Here very characteristic exposures of the Aldgate sandstone 

 occur, which can be seen resting unconformably on aplitic 

 and highly-foliated crystalline rocks, the former with a strike 

 120° east of north and dip 25° south-west, and the latter with 

 foliated strike 10° east of north and dip 75° easterly. The 

 grits are in places coarser than those which occur near the 

 Aldgate township, and by following them down the creek they 

 are seen to include rolled pebbles. In one instance, at least, a 

 fragment of the older series was observed to be included in 

 the upper beds near the line of junction, and also a rolled 

 nodule of ilmenite. Lately I have had the privilege of being 

 accompanied in a visit to the Aldgate section by my col- 

 league. ]\Ir. D. Mawson, B.Sc. Professor T. AV. Edgeworth 

 David. F.R.S., and Professor Skeats. D.Sc, who concurred in 

 the interpretation that had been given to the beds. 



The granite near Melrose's belongs to a much larger patch 

 of the Pre-Cambrian beds than that which is exposed near 

 Aldgate Station. It lies to the north-east of Stirling East, and 

 can be seen on the main road going to Carey's Gully, about 

 200 yards from the Stirlinq- East public school. It goes north- 

 westerly to an unused north-and-south district road, and 

 through Sir John Downer's and other properties to the dis- 

 trict road between Piccadilly and Wood house, for three- 

 quarters of a mile, beyond which it cannot be traced in that 

 direction, in consequence of the ground falling suddenly awav 

 to low cultivated flats. On the main road to Woodhouse and 

 the old sawmill it is clearlv defined, but verv rotten ; and in 



