650 FOLIATED GEANITES IN EASTEEN SUTHEELAND. [NOV. 1896, 



tendeDcy will be, by chemical interchange and osmotic action, to 

 bring the intrusive rocks and those into which they are intruded 

 more and more to resemble each other. Granite in small veins , 

 dykes, and sills can have been formed only in a very hot matrix, in 

 which heat would remain during long periods of time — conditions 

 most favourable to the extensive physico-chemical changes of the 

 intrusive and the intruded rocks. The Authors show how much 

 material of the granite has been derived from the matrix of the 

 intrusions, and we must also consider the loss of components from 

 the granite to the advantage of the matrix. Notwithstanding such 

 evidence as this, and much more of the same nature, a large school 

 of geologists persist in referring all the variations in igneous rocks 

 to internal differentiation and ignore chemical and physical osmosis. 



The Peesident also spoke. 



Mr. Geeenly, in reply, adduced cases where lenticles of granite 

 occurring in the schists could not be seen to have any communication 

 with any other granite-masses. These supported the view that the 

 granite might not be wholly foreign matter. Referring to remarks 

 by Gen. McMahon and Mr. Teall, he had never yet seen any region 

 of crystalline schists in which there was not abundant evidence of 

 intense earth-movement and deformation. This seemed a fact of 

 the first importance in the study of these rocks. But the time was 

 probably still far distant when it would be possible to generalize 

 concerning them without considerable reserve. He much regretted 

 the absence of Mr. Home. 



