20 PROCEEDINGS OP THE ACADEMY OP [1886. 



and scattered indiscriminately througliout the mass." (Geo- 

 logical Magazine, 1861, vol. 3, p. 533.) 



All of these observations relate to the external appearance of 

 these inclusions. No one of these writers has given us an intima- 

 tion of the microscopic or chemical nature of their internal 

 structure. In this respect Prof. J. A. Phillips has greatly sur- 

 passed his predecessors. 



In the Quarterly Journal of the Geological Society, vol. 36, p. 

 1, this author describes granites and their inclusions from numer- 

 ous British localities. The Cornwall granites at Lamorna, Zennor, 

 and Luxulyan contain numerous black patches, angular, fine- 

 grained and composed of quartz and mica. The granite of Shap 

 in Westmoreland encloses numerous well-defined, dark, round 

 patches, fine-grained and varying in size from i to 15 inches in 

 diameter. 



In Scotland, the Aberdeen granites (metamorphic, Haughton) 

 contain foliated, subangular inclusions of black mica. 



In Ireland, the granite of Newry (metamorphic, Hull; igneous, 

 Kinahan) aflfords inclusions which are apparently concretions. 

 The Mourne granite (eruptive) contains ovoid and angular, fine- 

 grained dark masses of mica and quartz. 



This author derives the following conclusions from these 

 observations: 



These granitic inclusions are of two distinct kinds. The first 

 is the result of an abnormal arrangement of the constituent minerals. 

 The second represents the enclosed fragments of other rocks. Of 

 the first, the outline is more or less ovoid, and they are essentially 

 a part of the including granite. The dark color is due to the 

 quantity of mica and hornblende. A second nodule contained in 

 the first, is indicative of concretionary origin. 



The formation of rounded inclusions in granites is believed to 

 be contemporaneous with the solidification of the mass, and 

 similar to that of the well known Napoleonite or orbicular 

 diorite of Corsica. 



Of the second class, the inclusions are irregular in outline, 

 schistose in structure, traversed by quartz veins or divided by 

 strings of granite. They are frequently unaltered, and are easily 

 recognized as fragments of gneiss, hornblendic and micaceous 

 rocks. 



In our own country, Professor Irving, in his report " On the 



