part 2] SOUTHEEN EYEE PETs'INSULA. 133 



bands, but botb were part of one mixing, apparently ' sheared.' 

 At Castle Cornet (Gruernsey) fine interbanding of gneiss with 

 aplite was trav^ersed by residual aplite across fractures of the 

 structure such as the Author described. The mixing of aplites 

 and granites, or of aplites and more basic matter, was again similar 

 at Elizabeth Castle (Jersey) and at Ronez ; but here the shearing 

 was absent. 



There were no garnet-rocks in the Channel Islands, which 

 might be explained by the moderate amount of biotite and the 

 comparatiye absence of augite. The speaker wished to know 

 whether the Eyre Peninsula produced eyidence of 'banded diabase'' 

 with long hornblendes developed in the parting planes by pressure, 

 as seen in the east of Gruernsey. 



Mr, W. Campbell Smith asked the Author whether the horn- 

 blende-pegmatites were always associated with included patches of 

 the amphibolite series in the granite-gneiss. Mr. F. Debenham 

 had mapped an area of biotite-granite in South Victoria Land, in 

 which included patches of para-pyroxene-granulites were always 

 surrounded by hornblende-granite of a peculiar type. The sugges- 

 tion, not yet worked out, was that the hornblendic facies was the 

 result of absorption of the pj'^roxene-granulite by the biotite-granite. 

 He was disappointed to learn that the Author considered that 

 myrmekite could be formed during the final stages of consolidation 

 of granite, and that it was not peculiar to gneisses. With regard 

 to a previous speaker's remarks on Stillwell's basic rocks, he was 

 inclined to think that a fair case had in fact been made out for 

 their beino- dyke-rocks. The rocks of Adelie Land and those now 

 described showed man}^ points of resemblance. It would be inter- 

 esting to hear the Author's opinion of Stillwell's work in this 

 connexion. 



Dr. J. W. EvAWS remarked on the similarity of the rock- 

 tj^pes described b}' the Author to those of Peninsular India. He 

 believed that rocks of charnockitic type owed the j)resence of ortho- 

 rhombic pyroxene to the absorption of argillaceous strata, resulting 

 in the presence of a considerable amount of alumina which, in 

 combination with silica, used up all the lime in the formation of 

 anorthite in plagioclase, leaving none for diopside. 



The AuTHOE stated, in reply to Dr. Wade, that the rocks of 

 Western Eyre Peninsula were petrographically distinct from the 

 series now dealt with, and constituted in fact a new series in the 

 Pre- Cambrian sequence. 



He stated, in reply to Mr. J. F. N. Green, that the parallel 

 which had been drawn with the Laurentian tract of Ontario 

 applied, not only to the gneisses themselves, but to the pre-existing 

 sediments now highly metamorphosed. With regard to the rela- 

 tionships of the associated amphibolites, he knew of no closer 

 parallel than the example which the Ontarian region afforded. 



No ' banded diabases ' of the nature described by Mr. Pljnnen 

 had been met with in the area investigated. 



In reply to Mr. Cam^^bell Smith, he said that the hornblende- 



