256 



material having been laid down, even by floating ice ; whilst 

 the limited variety of included pebbles is a further difficulty 

 in assuming such an origin. To refer the beds to a crush 

 conglomerate is equally out of the question, so that the diffi- 

 culty must be left for a possible future solution. 



The Pre-Cambrian beds are found underlying the basal 

 grits near the southern extremity of the ridge, forming one 

 of the south-western escarpments of the Barossa Ranges. The 

 beds consist of a very coarse pegmatite, penetrating a true 

 mica schist (mostly biotite), with accessories of beryls, tour- 

 maline, and other minerals. The beds are highly foliated, 

 showing a strike of 10° west of north, and a dip at 78° east- 

 erly. The exact junction between the Cambrian and the Pre- 

 Cambrian beds cannot be seen at surface, as a narrow area of 

 a few yards of grass separates the two, but the change is 

 abrupt and strongly defined. 



Other Localities. — Time has not permitted careful ex- 

 amination of other outcrops no less interesting than those 

 just described. Of these the following may be mentioned : - 



Forest Range. — This section (to which my attention was 

 called by Mr. Robert Caldwell) occurs near the main road, 

 five miles west of Balhannah. It presents a bold scarp to the 

 east and south, about 200 feet in height. In lithological 

 features it closely resembles the Inman Valley outcrop, in 

 being a coarse conglomerate, with gritty matrix. Expo- 

 sures of the conglomerate beds, much decomposed, can be 

 recognized for most of the distance from Carey's Gully to the 

 great outcrop of the Forest Range spur. The Pre-Cambria,n 

 slates, etc., follow the range on the east side of Carey's 

 Gully. 



River Torrens and Houghton. — A very interesting ex- 

 posure of these beds can be studied in the Torrens, near the 

 confluence of the Sixth Creek, and higher up the stream. 

 The older series form a hill rising abruptly from the Tor- 

 rens, to a height of seven or eight hundred feet. Its ser- 

 rated and precipitous faces have suggested the local name of 

 ''the Devil's Staircase." The river has cut its way throug^h 

 its lower slopes and exposed fine sections. The beds are in- 

 tensely altered slatesi, foliated, with felspar and quartz de- 

 veloped along the planes of foliation, giving the roek a 

 gneissic character. Larger lenticles of a granitoid character 

 are frequently present. On the western and southern sides of 

 these older rocks the basal grits of the Cambrian series out- 

 crop at a lower angle of dip. They closely resemble the il- 

 menite grits of Aldgate, with an occasional pebble included. 

 The junction of the two series can be traced to Houghton, 



