198 AUSTRALASIAN ANTARCTIC EXPEDITION. 



Contrary to Fermor's supposition we find on the close examination of a given 

 garnetiferous area that some rocks may contain garnet while others do not. In all 

 localities on the Cape Gray Promontory most rocks have been described with garnet, 

 but in each case there are types without garnet. In some cases we have described the 

 incipient stages of garnet formation. Further, we have found that the garnet-forming 

 conditions are highly localised in the garnet hypersthene felspar gneisses of Stillwell 

 Island and the Cape Pigeon Rocks. They may be present at one end of a specimen 

 Sin. long, while totally absent at the other end. In these the evidence is quite definite 

 that the garnet has formed by reactions between existing minerals without fusion, 

 and the metamorphic nature is undoubted. Such pronounced variation is scarcely 

 compatible with the infraplutonic zone hypothesis. 



The infraplutonic hypothesis has been advanced also without consideration of 

 those instances in which garnets are known to be products of magmas. It is well known 

 that some garnets, like melanite, appear in alkaline volcanic rocks, and we also found 

 garnet at Cape Denison appearing both in a large crystal, Gin. in diameter, and in graphic 

 intergrowth with quartz in the same pegmatite associated with the granodiorite gneiss 

 in which garnets are absent. We do not doubt at present, therefore, that some garnets 

 may form directly from solution. 



Until Fermor discusses this mode of formation of garnet and distinguishes the 

 infraplutonic zone from the kata zone of metamorphism and points out its relative 

 advantages, a geologist will be unable to use his conception. For the present we must 

 conclude that it does not give a reasonable account of the origin of the charnockite 

 series. 



4. THE KODURITE SERIES. 



We have turned to the short accounts available of the kodurite series to discover 

 whether this remarkable series, which is responsible for the infraplutonic hypothesis, 

 is considered to possess any metamorphic traits. At the commencement we notice 

 that Fermor* assumes that certain gneissose granites gain their foliated character 

 because they were intruded at the time of the folding of the Dharwar series, while other 

 granites, which were intruded subsequent to this series, have only a banded structure 

 due to flow. We, therefore, anticipate an incomplete appreciation of metamorphic 

 individuality, while it has already been pointed out by Crossf that further proof is required 

 before geologists can be expected to accept the view of igneous origin. 



In this publication we find that the kodurite series is stated (p. 244) to be part of 

 an ancient group of rocks which include the charnockite series, a gneissose granite, calc 

 gneisses, and the khondalite series (metamorphosed sediments). As we consider these 



* " Manganese Ore Deposits of India," L. L. Fermor, Mem. G.S.I., XXXVII., pt. 2, 237. 



t " Problems of Petrographic Classification suggested by the Kodurite Series of India," W. Cross, Journ. Geol., XXII., 

 1914, p. 794. 



