THE METAMORPHIC ROCKS OF ADELIE LAND. 8TILLWELL. 199 



rocks possess metamorphic character*, and as they all outcrop in the form of parallel 

 bands, it is probable that the kodurite series, which also possesses the banded arrange- 

 ment, likewise possesses such characters. 



Fermor admits the likeness to metamorphosed manganiferous sediments in some 

 cases, but he is influenced by the belief that there is little or no evidence that the kodurite 

 series has suffered much by earth movements. There remains, however, a suspicion 

 that the " suffering from earth movements " means nothing more than the presence 

 of mechanical crush structures. 



Even if we admit, as in the case of the charnockites, the evidence of igneous origin, 

 there remains the possibility of a metamorphic character superimposed upon the igneous 

 character ; and, if this were so, the rocks must be classed as metamorphic, because 

 it is quite impracticable, as argued by Crook,* to classify altered rocks according to their 

 original condition. We notice (p. 250) that the kodurite family likeness extends over 

 types varying from acid to ultra-basic, i.e., there is a family characteristic, as in the 

 charnockites, which is independent of chemical composition, and which we interpret 

 as a metamorphic character. One of the supports of the igneous hypothesis is the 

 assumed magmatic differentiation, which depends on the observation that the more 

 basic rocks (p. 254), such as spandite rock, occur as large patches or streaks, surrounded 

 by zones of less basic composition, such as kodurite, in a general matrix of quartz felspar 

 or felspar rock. In a general report for 1914 it is stated f that Fermor is inclined to 

 replace this interpretation with the supposition of assimilation on a large scale, and to 

 consider that a granite magma has bodily dissolved entire manganese ore deposits. 

 Either of these hypotheses will be difficult to substantiate, but the discussion will not 

 be complete without a consideration of metamorphic differentiation or metamorphic 

 diffusion. 



The full and detailed account of the petrology of these rocks is not yet published, 

 but the information available suggests that there has not been full consideration of 

 possible metamorphic characters.^ 



"The Genetic Classification of Rocks," T. Crook, Min. Mag., XVII., 1914, p. 70. 



t " General Report of the Geological Survey of India for the Year 1915," C. S. Middlemiss, Roc. O.S.I., vol. XLV., pt. 2, 

 p. 103. 



J In addition to the two reference* quoted there is " The Systematic Position of the Kodurite Series, especially with 

 reference to the Quantitative Classification," L. L. Fermor, Rec. G.S.I., XLII., pt. 3, p. 208. 



