Ixxxii PROCEEDINGS OF THE QEOLOGHCAL SOCIETY, [vol. Ixxiii, 



instead of fringing out into innumerable sheets and veins, they 

 have made large compact bodies. In general the intrusions have 

 avoided the neighbourhood of the great overthrusts, and are to 

 be found chieflv in the interior of those belts of country which 

 had behaved as tectonic units. Thus in the South-Eastern High- 

 lands a train of plutonic masses extends from Peterhead into 

 Argyllshire, and in the Centi'al Highlands a somewhat less im- 

 portant train can be traced from the borders of Caithness to the 

 Ross of Mull. In each case the intrusions are largest and most 

 numerous towards the north-east, where the overthrusting had been 

 least, and the individual masses tend to have their long axes in 

 the common direction. All these facts go to show that, although 

 the great crust-movements were past, the intrusions were localized 

 and guided b}" a distribution of stress of the same general 

 character. 



In Northern Ireland the plutonic masses of Slieve Gallion, 

 Pomeroy, and perhaps others, seem to carry on in a general way 

 the line of the Newer Granites of the Highlands. Farther south 

 a parallel belt of intrusion, referred with some confidence to this 

 age, is represented by the Gallowa}^ granites and those of Castle- 

 wellan, Ne^vry, and Crossdoney in Ireland. Another belt, includ- 

 ing the Enghsh Lake District, the Isle of Man, and the long tract 

 of the Leinster granites, seems to mark the limit in this direction 

 of important Caledonian intrusions. In this bordering belt, 

 removed from the principal theatre of disturbance, the abrupt 

 boss-form tends to be replaced by a roughly stratiform habit, as is 

 clearly indicated by the underlying position of the Skiddaw, 

 Eskdale, and Foxdale granites. Even here, however, contem- 

 poraneous stress is proved by a certain horizontal differentiation, 

 seen in an increasing acidity and richness in white mica towards 

 the northern edge of each mass. The Leinster granite-tract is 

 more complex, and seems to be the result of several intrusions. 

 The granites of the main chain are foliated and sometimes 

 crushed in a manner which indicates stress during and after their 

 consolidation. 



On the petrographical side there are some significant facts of 

 distribution. The name ' Newer Granites ' does not adequately 

 describe an assemblage of types which ranges from acid to ultra- 

 basic. In the Highlands, and especially in the large masses 

 situated toAvards the north-east, different rocks are often inti- 

 mately associated in a complex which may include peridotites, 



