of Salem and Barramahal. 167 



phyritic character, containing the same identical crystals of 

 felspar embedded in their masses. 



Near Indoor, some granite may be seen in large round 

 masses, with a perfect spheroidical structure, separating in 

 concentric lamina of an inch thick or more. This is the 

 only instance I have met with of this kind of structure in 

 granite, and as it is rather dark in colour, and its manner of 

 aggregation approaches to that of greenstone, in the partial 

 mixture and confusion of the ingredients, it might perhaps 

 be considered as a granitic variety of greenstone, in which 

 rock this structure is common. It is possible a similar rock 

 is alluded to by Dr. Ure, (Dictionary Chemistry, art. Gra- 

 nite,) which he calls rolling stones. Bakewell also alludes to a 

 similar structure in granite, where he says : " Granite is occa- 

 sionally found in globular masses, which are composed of 

 concentric spherical layers, separated by a granite of a less 

 compact kind, and enclosing a hard or central nucleus. 

 These globular masses are often three or four yards or more 

 in diameter, and are either detached or embedded in granite 

 of a softer kind." 



The whole of the granite in the Barramahal is more or 

 less striped or veined; the hornblende being occasionally 

 collected into stripes of a dark colour, in which hornblende 

 is in so large a proportion as to form a perfect syenite. 

 These veins are contorted and twisted in all directions ; 

 sometimes in perfect zigzags, and sometimes are so perfect- 

 ly parallel as to impart a slaty character to the cleavage 

 of the rock, and thus transform it into a gneiss. Occasional- 

 ly masses of porphyritic syenite may be seen embedded in 

 the mass, and sometimes the separated portions of the em- 

 bedded rock may be traced easily, as being parts of the 

 same broken mass, by their conforming and similar masses. 

 In some cases the veins of the granite are bent round con- 

 formably to the portions of embedded syenite, as figured by 

 McCulloch in gneiss of Coll (Western Isles, plate 27, fig. 1); 



