346 



C. A. SUSSMILCH. 



H. The Peneplains.— Reference has already been made, 

 when describing the Yass-Canberra tableland, to the prob- 

 able existence of three distinct peneplains. It is now 

 proposed to discuss the evidence in support of the existence 

 of these throughout the southern tableland generally. 



1. The Monaro Peneplain. — This constitutes the general 

 surface of all the subdivisions of the southern tableland. 

 It has been cut out of a complex series of lower palaeozoic 

 sedimentaries and metamorphic rocks, extensively intruded 

 by acid igneous rocks. The sedimentaries consist mainly 

 of shales, limestones and tuffs, the metamorphic rocks con- 

 sist of gneiss, mica and talcose schists, phyllites, etc., 

 while the intrusive igneous rocks consist mainly of granite 

 and quartz porphyry. The so-called Monaro plains and the 

 Yass plains are typical examples of this peneplain. In the 

 neighbourhood of the main divides which existed during its 

 formation, it splits up, finger-like, into mature valleys, 

 separated by residuals of the tableland out of which it has 

 been eroded ; this feature is well shown in the district to 

 the west of the railway line between Bredbo and Oooma. 



2. The Barren Jack Peneplain. — Throughout this area 

 occasional more or less isolated peaks occur, which rise to 

 an altitude of upwards of 1,000 feet above the Monaro 

 peneplain. These include the following : — 



Residuals of the Barren Jack Plain. 



Name. 



Section of the Southern 

 Tableland on which the\ 



Actual 

 Altitude, 



Altitude 



above 



Monaro 





occur. 





Peneplain. 







Feet. 



Feet. 



Mount Kosciusko* 



Kosciusko Tableland 



7,328 



1,328 



Mount Townsend* 



Ditto 



7,260 



1,260 



Mount Clarke* 



Ditto 



7,000 



1,000 



Mount Etheridge* 



Ditto 



7,000 



1,000 



Bimberry Peak 



Kiandra Tableland .. 



6,264 



1,464 



Half -Moon Peak ... 



Ditto 



6,144 



1,344 



Table-top Mountain 



Ditto 



5,850 



1,050 



Tindery Pie* 



Tinderry Tableland... 



5,307 



1,307(?) 



Lampe 



Yarrangobilly „ 



5,338 



1,338 



Barren Jack* 



Yass-Canberra ,, 



3,162 



1,162 



Narrungullen (?) ... 



Ditto 



3,411 



1,411 



Rob Roy ... 



Ditto 



3,585 



1,285(1)1 



