Yol. 56.] CEYLON ROCKS AND GRAPHITE. 615 



Discussion. 



Prof. BoNNEr expressed his sense of the importance of this paper, 

 on which he knew that the Author had expended great labour. It 

 was interesting to find so great a mass of ancient crystalline rocks 

 practically unaffected by pressure. The relations of the garnets, 

 felspar, and pyroxene were most interesting and suggestive, and so, 

 too, was the mode of occurrence of the graphite. He thought the 

 paper also very valuable as illustrating the formation of a root-like 

 graphic structure, which he thought implied crystallization under 

 obstruction, while the ordinary rectilinear ' graphic ' structure 

 (to which the name was originally given) implied that one of the 

 two minerals was not resisted by the other. 



Dr. J. W. Evans referred to the resemblance between the rocks 

 described in the paper and those of Southern India, of which 

 Ceylon was geologically an integral part. Towards the south of the 

 Indian peninsula the ancient sedimentary rocks disappeared, though 

 the widely-extended granitoid gneiss still continued. The most 

 remarkable fact, however, was the extraordinary development of the 

 charnockite-series of Mr. Holland, which appeared to be identical 

 with the present Author's pyroxene-granulites. These formed the 

 lofty mountain-masses of the Nilgiris and Annamallais, and were, 

 it seemed, the chief feature of the most elevated regions of Ceylon. 

 Graphite also occurred in Southern India, not only in dykes in 

 Travancore, but in flakes in holocrystalline igneous rocks both in 

 Mysore and in British India. 



The President also spoke. 



The Author stated, in reply to Dr. Evans, that small flakes of 

 disseminated graphite occurred in several of the igneous rocks of 

 Ceylon. He distinguished between the graphite occurring thus as 

 a subordinate rock-forming mineral, and the vein-graphite which 

 had been deposited after the consolidation of the rocks in which it 

 was found. In conclusion he heartily thanked the Eellows for the 

 very kind way in which they had received his paper. 



