RUM. MINERALS. 603 



which I observed were imbedded distinctly in glassy 

 felspar among the rocks of Halival. They were about 

 two inches in length, and half an inch in thickness. 

 The same mineral is sometimes found in that concre- 

 tionary state which is known by the name of coccolite. 

 In this case it is usually of a pale olive green, and 

 translucent. Another remarkable mixture occurs, namely, 

 that of the coccolite with the laminar and massive, augit. 

 In this case the same appearance takes place which 

 I have described as occurring in the granular rock ; 

 the laminar portions persisting in continuous faces every 

 where interrupted by the interposed coccolite, and thus 

 acquiring an aspect somewhat similar to that of graphic 

 granite. In one instance there occurred cavities in a 

 trap vein where a felspar of an olive green colour was 

 traversed by large crystals of black augit. The olive 

 .green augit is also met with in two other states. In 

 the one it appears in the form of a crowded mass 

 of crystals without any felspar interposed, and con- 

 siderably translucent. In the other it constitutes a solid 

 mass, with an irregularly plated fracture ; being so tough 

 that the hammer of four pounds weight was almost 

 incapable of detaching a fragment, or breaking one 

 already detached. The green hue of this mineral 

 is less common than the black, the most numerous 

 specimens appearing to be of the latter colour ; in which 

 case, when they form rocks, it is very difficult to dis- 

 tinguish them from hornblende. 



In the neighbourhood of Harris I procured some speci- 

 mens of hypersthene, a substance already described as 

 existing in Sky. In mineral character it is not to be distin- 

 guished from the specimens of that island, and it occurs in 

 compound veins traversing the augit rock. It did not 

 appear to constitute any portion of the rocks in the vici- 

 nity of the veins, as it does in Sky. The vein is a nearly 

 equal compound of opake white felspar and hypersthene, 



