28 



that of the west side of the anticline was 77° westerly. The protru- 

 sion of the granite is in the line of strike of this anticline and 

 northward. Near this place cyanite, a rather rare mineral, is 

 found in quartz veins. A line grained, very hard white sand- 

 stone occurs in sections 554 and 683, forming a bank-trending 

 nearly east and west, cleaving into almost right-angled blocks, 

 and quite local. Magnesian limestone and a seam of very hard 

 kaolin were noticed near Moppa, and a vein of baryta on the road 

 near Greenock. 



At Tanunda, between sections 43 and 38, the river has broken 

 through quartzites, sandstones, and micaceous slate, which proba- 

 bly was the original barrier above which the waters of the upper 

 lake were confined. By the strike o f intervening masses of 

 similar rocks they appear as a continuation of those forming the 

 highest ridge between Greenock and Nuriootpa. Another barrier, 

 very thick, occurs north of Jacob's Creek, and beyond Rowlands 

 Flat the banks of the river become high and precipitous, attaining 

 from its sharp south-easterly bend for several miles an elevation 

 of about 200 feet. The base is formed of the old rocks dipping 

 at steep angles, mostly easterly. The greater part above is 

 formed of conglomerates, gravels, clay, and sand. At the ford at 

 Both's Mill, sections 560 and 1806, and farther past the tillage 

 at Rosenthal, clay slates, frequently very fine grained and fissile, 

 come in and reach to the summits of the hills, rising 200 to 300 

 feet above the river bed, and narrowing it extremely. The 

 gradual wearing through these hills obviously opened a way for 

 the escape of the waters accumulated over the Lyndoch Yalley. 



Above the clay slates, and intercalated with them, occur 

 thimier or thicker seams of crystalline limestone, mostly of a 

 bluish or grey tint, and also iron spar, with perfect cleavage, is 

 met with. In the bed of the creek, about section 1700, a per- 

 fectly black coarse slate is found locally, and in section 1692 a 

 dyke occurs of volcanic or pseudo-volcanic rock, being formed of 

 large and smaller angular fragments united by a homogeneous 

 cement. It is traceable in the direction of its strike, south-west 

 and north-east, for several hundred yards, and has a width of 20 

 or 30 yards. In the neighbourhood also occur jasper and chalce- 

 dony in large blocks, now no longer to be seen in situ, but re- 

 moved for road metal or lying along the fences. About section 

 806 the highest point is reached for this part, called Schoof 's Hill. 

 It is composed of a highly indurated silicious slate rock, with 

 very imperfect clea^'age, flanked eastward by a ridge of soft mica- 

 ceous slates. 



North of this, in sections 101 and 102, this limestone assumes 

 large proportions, forming a hill, on which the Wheal Nitschke 

 Copper Mine was worked. 



i 



