Vol. 60.] OF THE EAST-CEXTRAL HIGHLANDS. 449 



in the Highlands. Tracts of metamorphic rocks with which single 

 workers could deal were too small for general purposes : while the 

 great continental masses of them in other countries could only be 

 sketch-mapped during the lifetime of the present generation. In 

 the Scottish Highlands we had a metamorphic region large and 

 varied enough to be of world-wide interest and application, and yet 

 it could be mapped in great detail, because it was possible to bring 

 the united efforts of a whole staff of surveyors to bear upon it. 

 Herein lay the very great value of the work of the Author and his 

 colleagues, work which might have other applications than those of 

 pure science. 



The Author thanked the Fellows present for the kindly way in 

 which they had received his paper. With regard to the suggestion 

 that rocks of various ages might be involved in what may be termed 

 a ' Moine-Gneiss ' area by folding, the Author pointed out that the 

 newest or most recent must be older than the oldest intrusion that 

 cuts the folding. As an illustration of this important point, he 

 referred to the Meall-Gruaim ' augen-gneiss ' shown on the map to 

 the south of Gilbert's Bridge, and suggested its pre-Torridonian 

 age. 



