THE METAMORPHIC ROCKS OF ADELIE LAND. 8TILLWELL. 101 



the Loch Maree and Gairloch district in the Scottish Highlands. The theory of an 

 amphibolite intrusion is quite consistent with the general statement (p. 115) that it is 

 almost a universal rule that the limestone near the contact is filled with various silicates 

 which have been developed in it, while the inclusions actually present in the granite 

 near the contact are composed of amphibolite or some allied rock. 



The unrecognised presence of metamorphic diffusion is upheld by Adam's and 

 Barlow's discussion (p. 115) of the question " Has the granite gneiss anywhere actually 

 dissolved the invaded rock ? " Several instances are quoted to show that the granite 

 magma has been rendered basic by absorption of amphibolite. The peculiarities of the 

 gneiss are those which have been received long after consolidation, and the effects of 

 solution by the primary magma can only be interpreted with the greatest care. In 

 this case the gneiss is conceived as a molten magma and the conceptions of flowing 

 gneiss and the confusion of bedding and foliation are dangerously wrong and court 

 erroneous interpretation. It is stated (p. 117) that where the granite runs into a corner 

 between two tongues of amphibolite a basic development of the granite is seen also, due, 

 in all probability, to a partial solution of the invaded amphibolite ; that the products 

 of solution bear (p. 122) a marked resemblance to the grey gneiss. This " solution " 

 may readily be another case of that process which has been called metamorphic diffusion. 



It is interesting to note (p. 114) that in one area of gneissic granite, that in the 

 township of Methueu, southern portion of the Kasshabog Lake, amphibolite inclusions 

 are abundant and appear in a linear belt parallel to the foliation. Again (p. 118) the 

 limestone, as shown on the Bancroft sheet, has a number of belts of amphibolite parallel 

 to the strike. This recognition of linear development is suggestive of dyke origin. 



With regard to the amphibolites (Group 26) which appear as inclusions in the grey 

 gneiss, Adams and Barlow state (p. 121) that they are portions of rock forming the walls 

 or roof of the batholith which had fallen into the granite magma and had partaken of 

 its subsequent movements. He also adds that there is positive proof that this is the 

 correct and only explanation in several parts of the area. The positive proof, however, 

 is not convincing. Even if there were no reason to believe, as affirmed by Adams 

 and Barlow (p. 122), from the form or composition that they are ever due to magmatic 

 segregation, there will remain the hypothesis of a broken and disrupted dyke. I fail 

 to see even how the form, much less its composition, can preclude the hypothesis of 

 metamorphosed primary magmatic segregation products. We find on page 160, fig G, 

 an illustrative sketch in the memoir actually showing an amphibolite in the first stages 

 of disruption, and on page 76, fig. A, we see the characteristic lens shape similar to that 

 of fragments which have been proved to be part of dykes. Again, fig. B, page 76, 

 we see again the disruption of the amphibolite inclusions. We therefore see that the 

 Canadian evidence is sufficient, apart from the evidence from Cape Denison or the 

 Scottish Highlands, to show that a detached fragment of amphibolite, enclosed by 

 gneiss, is not necessarily to be regarded as earlier than the invading granite in the 

 metamorphic areas. This fact lends considerable support to the theory that many of 



