Vol. 70.] OF THE COUNTRY AROUND KTTNTLY. U93 



named, he asked whether the fluxion-bands showed any signs of a 

 mixed magma. The association of minerals described by the 

 Author in the cordierite-rocks was interesting, and the occurrence 

 of sillimanite and spinel was to be expected ; but the speaker 

 had heard no mention of corundum, which was often one of the 

 ' faithful companions.' He would be interested to know whether 

 corundum had been observed in these rocks. 



Dr. J. W. Evans thought it remarkable that a mineral con- 

 taining so much silica in proportion to the magnesia and iron- 

 oxide as cordierite did, should occur as a result of the contact- 

 relations of two norites. He was glad that the Author had 

 referred to the case described bv Sir Thomas Holland, where garnet 

 appeared to be formed by the alteration of hvpersthene. In the 

 Indian rock the colour of the garnet was so remarkably- similar to 

 that of the pink vibrations of the hypersthene. that one was 

 irresistibly led to the conclusion that they were related. The 

 conversion of the hypersthene into garnet involved a considerable 

 change in chemical composition, which would, however, be some- 

 what less if the garnet were pyrope. 1 He would like to know 

 whether the chemical composition of the garnet in the case 

 described by the Author had been ascertained. 



Lady McRobert stated that she was familiar with the district, 

 and knew the extreme difficulty experienced in tracing the boun- 

 daries of the different zones ; she therefore wished to compliment 

 the Author heartily on the successful way in which he had earned 

 out the work. 



With reference to Dr. Elsden's question, as to whether there was 

 any evidence of fluxion-banding due to the streaking-out of different 

 magmas, the only such example in the district of which she was 

 aware was a very striking alternation of bands of black troctolite 

 and pale allivalite, which of course only differed slightly in mineral 

 composition. She thought that she was correct in stating that no 

 corundum had been found in association with the cordierite and 

 sillimanite. 



Prof. W. W. Watts, replying on behalf of the Author, thanked 

 the Fellows present for the kind reception of the paper. 



In reply to Dr. Elsden, he stated that the fluxion-banding was 

 due to arrangement of minerals rather than to the streaking-out of 

 differentiated bands. He pointed out the complexity of the rock- 

 relations which the Author had had to unravel, and said that the 

 district was now ready for additional work on the lines which the 

 Author had laid down but was unable, owing to his absence in 

 India, to follow out. 



1 [A qualitative analysis has shown the presence of both iron and lime 

 in great quantity, and a mere trace of magnesia. The garnet cannot, therefore, 

 be pyrope.— W. R. W., April 23rd, 1914.'] 



