Palaeozoic Geologij of Victoria. 121 



The above description also concisely describes the features of No. 

 68. The occurrence of this rock in shown in Map 4, near the head 

 of one of the branches of Ii-onstone Creek. The outcrop, however, 

 is very limited, being partly surrounded by late Kainozoic sands and 

 graved. 



The relationship to the igneous rocks of the district is not shown, 

 l)ut it is almost certainly later than the earliest members of the 

 Snowy liiver Series, which show here various stages of shearing 

 Avith the development of porphyroids. Some of these outcrop in the 

 stream bed a short distance below the ceratophyre. 



From tJie chemical analysis of No. 68, applying the American 

 Classification, it is interesting to note that it falls into the persodic 

 Subrang, noyangose, of liparase, the per-alkalic Rang.(l) of 

 britannare, the quardofelic Order (4) of persalane. Class 1. 



Analysis and Molecular Ratios and Classification. 



SiO., - 72.41 - 1.207 - - Quartz - 29.28 



A1.A - 14.38 - 0.141 - - Orthocla.se - 0.55 



Ff-A - 2.94 - 0.018 - - Albite - 58.16 



FeO - 0.85 - 0.012 - - Anorthite, - 3.33 



MgO - 1.18 - 0.029 - - Corundum - 2.84 



CaO - 0.87 - 0.015 - - Hyperstheue 2.90 



Na.,0 - 6.86 - 0.110 - - Magnetite - 2.32 



K.,6 - 0.13 - - - - llmeiiite - 0.45 



H^,0-t- - 0.67 - - - - Hematite - 1.28 



H.^0 - - 0.04 



CO., - - - - . Class - - 1 



TiO'., - 0.26 - 0.003 - - Order - 4 



P„Oj - 01 7 - 0.001 - - Rang - - 1 



m\i6 - 0.09 - 0.001 - - Subrang - 5 



Total 100.85 Magmatic Name, Noyangose. 



S.G. 2.63 



Granite Eocl-x. — Only one small occurrence of granite- has been 

 noted in the area included in the map. It is limited to an exposure 

 of a few chains extent along the bed of one of the branches of the 

 Tara Creek, No. 98. On the west it is in contact with the frag- 

 mental igneous roi'ks of the Snowy River Series. No evidence of 

 contact alteration of these rocks was noted, nor . have any dykes 

 or offshoots of granitic rocks into them been observed. It is prob- 

 able, therefore, that the granite is the older rock. A much more 

 extensive outcrop of granite closely similar macroscopically, and in 

 thin sections also, occurs a few miles to the east of the Tambo River, 



