﻿394 MR. T. 0. B0SW0RTH ON METAMORPHISM [Aug. I9IO, 



Some parts of this rock, which are very schistose, contain a largo 

 amount of tourmaline, in lustrous black needles with parallel 

 arrangement. But sometimes, where the rock is less schistose, 

 both kyanite and tourmaline are large. 



In addition to these minerals, thin sections show the presence 

 of staurolite, abundant stumpy prisms of rutile, and also some indi- 

 cation of tufted needles of fibrolite enveloped in muscovite and 

 fringing kyanite. There is only a small exposure of this rock, seen 

 as a narrow strip for some 40 yards along the strike. It seems 

 to be inseparable from a peculiar band of epidiorite. There is no 

 remarkable amount of pegmatite here, and the granite is 2 miles 

 distant. 



Occurrence in other parts of the Highlands. 



Tourmaline is common and widespread in the Highlands. In 

 the Moine Bocks as a constituent of pelitic gneiss, besides the two 

 instances in Mull, it has been noticed 



(1) On the west side of Lake Luichart (Boss-shire), by Dr. Peach, 1 in a thin 



bed of mica-schist. Some specimens from this neighbourhood show 

 stout prisms up to about half an inch in length, abundant in a 

 garnetiferous quartz-muscovite-biotite schist of medium coarseness, in 

 which knots and veins of quartz occur. 



(2) Near Loch Hourn (Inverness-shire) by Mr. Clough. 



(3) In the Strathfarrar district (Inverness-shire) by Mr. Hinxman. Some of 



these crystals are an inch or two long and an inch thick, in rather 

 coarse quartzose muscovite-schist. Very large crystals occur here in 

 pegmatite veins. In a letter Mr. Hinxman remarks that ' there is 

 no evidence to connect the tourmaline of Glen Strathfarrar with any 

 visible intrusion of granite.' 



It is in the old pegmatite veins and patches that the tourmaline 

 is most common : to quote only a few instances : — In the Moine 

 Schists of Pannich Porest, Dr. Home 2 found small pegmatite veins 

 with prisms of tourmaline. In the Moine rocks of the Loch Fannich 

 district, Mr. Pocock 3 mentioned pegmatites containing tourmaline 

 crystals 4 or 5 inches long. Concerning these, Dr. Home says in 

 a letter 



' We never connected these pegmatites with the Newer Granites, but regarded 

 them as connected with the regional metamorphism.' 



In the Moine rocks of Inverness-shire, Mr. Hinxman and 

 Dr. Crampton find similar tourmaline-pegmatites. 



In other Highland gneisses also tourmaline is common, 

 Heddle 4 gives a long list of localities from which it is recorded, 

 sometimes in quartz-veins and pegmatites, and sometimes in schists. 

 Numerous specimens may be seen in the Heddle Collection in the 



1 Summary of Progress of Geol. Surv. for 1898. 



2 Ibid. p. 12. 3 Ibid. pp. 16 & 17. 



* ' Mineralogy of Scotland ' vol. ii (1901) pp. 74-75. 



