THE METAMORPHIC ROCKS OF ADEL1E LAND. 8TILLWELL. 115 



interpreted as an example of metamorphic diffusion. With this explanation it is to be 

 expected that the Traboe type of schist should only be found near the margin of the 

 serpentine whose metamorphism has been shown to develop additional heat. Hence, 

 on the present available evidence the Traboe and the Landewednack schists can only be 

 looked upon as slightly different facies of the same primary rock. There is at present no 

 valid reason for discrimination in age. Further, the possibility that the Traboe schists 

 represent an igneous rock intrusive into the serpentine has not been disproved. 



Accompanying the Laudewednack schists (p. 50) are streaks and nodules of epidosite, 

 and it is very interesting to note that Flett looks upon these as due to some kind of 

 segregation during metamorphism. They are similar to the Cape Denison epidosite, 

 which we have called a metamorphic differentiation product. Epidosites also occur 

 abundantly (p. 36) among the green schists and granulites of the old Lizard Head series. 

 Here Flett considers them as facies of the other rocks rather than types entitled to 

 recognition as a distinct group, and states that some of them are segregations, nodules, 

 and vein-like masses in the hornblende schists produced either by weathering before 

 shearing, or by chemical segregation during movement ; that others are probably due 

 to weathering of a fine type of hornblende schist and hornblende granulite ; that others 

 are quartzose granulites in which epidote may represent volcanic detritus or ashes, 

 or may be a secondary infiltration during metamorphism. It seems to me that such 

 an aspect is only possible when metamorphic rocks are denied their own special 

 individuality, because epidosites do not fit into any sedimentary or igneous rock group. 

 In this case again the epidosites can be explained as metamorphic differentiation 

 products. 



The gabbro dykes (p. 81, et seq.), whose foliation we have contended is in no way 

 connected with their injection, occur only in the serpentine. In addition to the dykes 

 there are intrusive bosses, the largest of which is the Crousa Downs Gabbro. These 

 gabbros were grouped by Teall into 



1. Gabbro Schists. 



2. Flaser Gabbro. 



3. Normal Types. 



Flett also considers them in this manner. The treatment from the standpoint of igneous 

 rocks is evident here in the nomenclature. Though the dykes are known to be 

 metamorphic, the igneous rock term " gabbro " is applied. The gabbro schists are 

 coarse-grained saussuritic hornblende schists which are a well-known type developed 

 from dolerite or diabase. The present coarse-grained character is not necessarily evidence 

 of the original coarse granularity of the gabbro. The flaser gabbro, which is the 

 prevailing type, is also a metamorphic rock, because it includes all those gabbros which 

 exhibit distinct evidence of crushing and recrystalhsation. The normal gabbros are 

 restricted to the neighbourhood of Coverack, and as one recognises the general 

 metamorphism of the Lizard, and also as a weak " fluxion banding " is mentioned, 



