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counter the white spots (turbid felspar) they sweep round them in graceful 

 curves. The water-clear substance is certainly in many cases biaxial and 

 therefore may be referred to felspar. It plays the role of ground-mass, and 

 actinolite needles often project into or lie embedded in it. The " eyes " 

 in the schist are composed of turbid felspar similar to that of the por- 

 phyritic epidiorites. In studying the green schists of the highly meta- 

 m orphic zone in the south-west portion of the Lizard peninsula we 

 meet with the usual difficulty of distinguishing between felspar and 

 quartz, as both minerals are colourless and possess approximately the 

 same refraction and double-refraction. The only satisfactory test, in 

 the absence of form, and twinning, is the determination of the uniaxial or 

 biaxial character of the grains by the use of convergent light. Quartz 

 certainly occurs abundantly in some of the schists, but appears to be rare 

 in those which can be definitely proved to have originated in consequence 

 of the metamorphosis of igneous rocks. The exact nature of the water- 

 clear felspar has not been determined. Reasoning from analogy we should 

 expect it to be allied to albite. Mr. ADAMS < 1 > has described hornblendic 

 and actinolitic schists, which seem to resemble in many respects those 

 above referred to, from certain rocks of the Quebec group. The water- 

 clear felspar in these cases gave a strong soda flame. 



It is interesting to note the differences between the actinolite-schist 

 from the south-western portion of the Lizard and the hornblende-schist which 

 forms the margin of the Poltesco dyke. In the one case the hornblende 

 is in the form of grains of nearly equal dimensions in the different direc- 

 tions, in the other case it is in the form of long acicular needles. As the 

 original rock in both cases appears to have been similar in structure and 

 composition the difference in the form of the hornblende is probably due 

 to a difference in the conditions of metamorphism. On comparing the 

 mode of occurrence of the two rocks it seems clear that the interstitial 

 movement has been greater in the case of the actinolitic than in that of the 

 hornblendic schists. The rocks above referred to are best studied in the 

 neighbourhood of Polpeor and between that locality and Lizard Head. 

 Everywhere along this portion of the coast the signs of intense mechanical 

 disturbance are apparent. 



One conclusion of general interest may be drawn from a study of the 

 metamorphic phenomena in the south-western portion of the Lizard. We 

 have seen that a clue to the origin of many of the green schists is given by 

 the " eyes " or lenticles which these schists contain. According to the view 

 we have adopted these " eyes " are portions of the original rock which have 

 preserved their characters to such an extent as to allow them to be 

 recognized. They are portions which, for some unknown reason, have 

 escaped the intense metamorphic action. Now, if this view be correct, it 

 will be found to be of widespread application. " Eyes " or lenticles of all 

 sizes from microscopic dimensions to areas occupying many square miles 

 on a geological map occur in regions of crystalline schists. It is to these 



(1) Report of the Geol. Survey of Canada for 1882. 



