CHAP. XI.VI 
THE ACID BOSSES OF SKYE 
391 
metamorphosed basalts from other parts of Skye, e.y. from Creagan Dubha, 
near the granophyre mass of Beinn Itearg. 1 The felspar occurs there in the 
same fashion, and in the same relation to epidote [2700, 2701]. In the 
specimens now described the chief minerals in the metamorphosed amygdales 
are those already named : others occur more sparingly, associated with them. 
In some cases there is a grass-green, strongly pleocliroic, actinolitic horn- 
blende, accompanied by a little iron pyrites [6615]. 
“ Epidote and various hornblenclic and augitic minerals are characteristic 
products in the metamorphism of amygdaloidal basalts in other regions : 
felspar with this mode of occurrence I have not seen except in Skye, where 
it seems to connect itself naturally with the abundance of zeolites in the 
amygdales of the non-metamorphosed lavas. It is to he observed that in 
these basalts from Loch Scavaig tire alteration is shown especially in the 
amygdales, the body of the rock not being greatly affected: this indicates a 
not very advanced stage of metamorphism. The production of uralitic 
hornblende, rather than brown mica, from the augite and its decomposition- 
products, seems to be characteristic of the metamorphism of basaltic as dis- 
tinguished from andesitic rocks, and is well illustrated by a comparison of 
the two sets of lavas near the Shap granite.” 2 
Mr. Harlrer, who is at present engaged in mapping the central region of 
Skye, has had occasion to go over a number of the localities (Creagan 
Dubha, etc.) originally cited by me, and, while corroborating my general 
conclusions regarding them, has been able to obtain much fresh evidence 
regarding the nature and extent of the metamorphism which the bedded 
basalts have undergone. The results of his investigations will be pub- 
lished when the Geological Survey of Skye is further advanced. 
(3) Relation of the Granophyre to the Gabfo'os . — That the granophyres 
invade the gabbros has been incidentally illustrated in the foregoing pages. 
But as the mutual relations of the two rocks in the island of Skye have been 
the subject of frequent reference in previous writings of geologists, it is 
desirable to adduce some detailed evidence from a region which has been 
regarded as the typical one for this feature in the geological structure of 
the Inner Hebrides. Ho geological boundary is more easily traced than 
that between the pale reddish granophyre and the dark gabbro. It can be 
followed with the eye up a whole mountain side, and can be examined so 
closely that again and again the observer can walk or climb for some dis- 
tance with one foot on each rock. That there should ever have been any 
doubt about the relations of the two eruptive masses is possibly explicable 
by the very facility with which their junction can be observed. Their 
contrasts of form and colour make their boundary over crag and ridge so 
clear that geologists do not seem to have taken the trouble to follow it out 
in detail. And as the pale rock undoubtedly often underlies the dark, they 
have assumed this infraposition to mark its earlier appearance. 
I will only cite one part of the junction line, which is easily accessible, 
1 Compare Trans. Hoy. Soc. Edin. vol. xxxv. p. 166. 
2 Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 361. 
