144 THE SHAP MItfOR INTENSIONS. [vol. lxxiV, 



The Author, in reply, thanked the Fellows for their reception 

 of his paper. With reference to the remarks made by the President 

 on the influence ot distance and the width of channel on the How 

 of the large felspars, he mentioned the interesting fact that the 

 narrowest dyke of the mixed series was the richest in felspar xeno- 

 crysts. Evidence on the point raised by Dr. Evans regarding the 

 direction of flow of material had been sought for in the field, but 

 the exposures were seldom sufficiently complete to make a general 

 statement possible. Where the fluxion-structure, however, was 

 most marked, the movement appeared to be vertical rather than 

 horizontal. In answer to Dr. Elsden, the Author pointed out that 

 the term ' xenocryst ' was generally applied to a crystal found in a 

 magma other than that from which it had separated out ; and the 

 term ' hybrid ' to a rock which was the product, not of a homo- 

 geneous magma, but of a mixture of magmas of different chemical 

 composition, even if more or less allied, as was the case in Skye. 

 In that sense the terms were used in the paper under discussion. 

 Spessartites were originally named after the locality from which 

 they were first .described, and as the name was now in general 

 use for lamprophyres of that type associated with magmas of a 

 similar nature, it was applicable to the rocks now described. 



