131 



shatter-zones have been indicated in this, paper. The reason 

 why the folding, if such occurs, is not obvious, and does not 

 cause reversal of dips, is probably that the movements have 

 been so intense that the anticlines and synclines have been 

 over folded and converted into a series of isoclines. 



To decipher the structure in a region of such complexity 

 as this it is absolutely essential to recognize persistent hori- 

 zons and to map such horizons out in detail. 



I claim to have discovered several such persistent 

 horizons : — 



(i.) The remarkable knoten-schiefer, which I have called 

 "paringite," has been observed at so many isolated points 

 along approximately the same line of strike that its value as 

 a persistent horizon is practically demonstrated. It makes 

 a good surface outcrop, which should be easily followed. 



(ii.) The associated crystalline limestone appears to 

 occur only in lenticular beds of considerable extent, but, 

 nevertheless, should prove to be a valuable horizon for map- 

 ping purposes. An outcrop of it occurs at Bull's Creek. 



(iii.) The purplish rock which, for want of a better 

 name, I have called 'soapstone," appears to be persistent. 

 I know of several places where it occurs, and is used as a 

 building stone. 



(iv.) The white saccharoidal quartzite described on 

 page 128 may be found of value. 



(v.) The belt of tremolite and actinolite schists typically 

 developed west of Mount Barker Junction is characteristic, 

 but yields little surface outcrop. 



It is to be noted that all the above horizons occur in 

 the Angaston district, forty miles to the north of BlakistoUj 

 in the same relative positions as they occur at Blakisto?i, 

 sli^owing their remarkable persistence, and indicating their ex- 

 treme value as stratigraphical landmai'ks. 



Suggestions to Future Observers. — I may perhaps be per- 

 mitted to make a few suggestions which will enable future 

 observers to save some time in preliminary investigations. 1 

 think the Blakiston to Mount Barker (mount) section should 

 be carefully studied, and the area just to the north and 

 south of it. I believe this section will afford the key to very 

 much of the geology of the district. I then suggest that the 

 observer become familiar with the paringite in some of its 

 typical occurrences, and then systematically map this import- 

 ant formation. In doing so many other problems will be 

 suggested . 



I think it likely that the valley in which Mount Barker 

 town lies is the axis of an important fold ; the sections from 

 Mount Barker town to Echunga, and from Echunga to Mac- 

 f2 



