268 THE CANADIAN NATURALIST. [Aug. 



the latter sort of gneiss predominates ; and there tourmaline often 

 occurs in it, forming a very beautiful rock. Occasionally the quartz 

 disappears, and a schistose syenite is the result. There are even 

 bands wherein very little slaty structure is discernible, and the rock 

 of which, did it occur in larger masses, would undoubtedly be termed 

 syenite. 



Mica schist would appear to exist in this district, at least in 

 such narrow bands as those of the micaceous gneiss above referred 

 to. It would seem also occasionally to occur as the rock of the 

 fahlbands hereafter to be described. 



Gneiss-granite. In many places to the south of Rossie, and 

 especially near the lead-veins on the farm of John Robb, the 

 gneiss, at least when hand-specimens of it are examined, exhibits 

 mere traces of parallel structure ; and on this account, as well as 

 because of its being finely granular, it might reasonably be termed 

 gneiss-granite. 



Granite. Besides the narrow granitic bands above referred to 

 which enter into the composition of gneiss, many veins of granite 

 occur which cross the gneissoid strata, sometimes in very great 

 numbers, and presenting an appearance similar to that described 

 by Macculloch as visible at Cape Wrath. 



Tourmaline rock. In the district of syenitic gneiss which lies to 

 the north-west of Rossie, there occur some irregular masses of quartz 

 in which tourmaline is so plentifully disseminated as to form the 

 schorlfels of German geologists. 



Crystalline limestone is very extensively developed in the 

 neighborhood of Rossie, and indeed it constitutes the storehouse 

 from which are obtained the greater number of the rare and beau- 

 tiful minerals, for which Rossie is celebrated. Like the same rock 

 in Canada, it is coarsely granular and sometimes saccharoidal. 

 The general color is white, although grey bands are of frequent 

 occurrence. These latter seem to owe their color to disseminated 

 laminae of graphite, — and indeed it is difficult to find a piece of the 

 limestone which is entirely free from this mineral. 



Diorite. This name may probably with justice be given to a 

 rock which occurs to the west of Rossie, and which forms the side- 

 rock of a vein of magnetic and iron pyrites which has been ex- 

 plored to a considerable extent for copper. It consists mainly of 

 greenish-white albite (some of the cleavage planes of which ex- 

 hibit a slight change of color), dark-green hornblende, and translu- 

 cent quartz. Besides these minerals there are also crystals of 

 sphene present in small quantity. 



