32 Jterieus — Geological Surrey — 



that the field-maps of De la Beclie also showed two divisions in- 

 the Metaraorphic area. Owing to the intense folding there is a con- 

 siderable amount of interplication, a feature well illustrated by 

 cuts in the text. The cliff between the Outer and Inner Hope, east 

 of Bolt Tail, shown as a section in the frontispiece to this memoir, 

 serves to illustrate the relation of the mica-schists to the hornblende- 

 epidote-schists in that particular area. The alternations of red and 

 green in the latter series of schists would be xery effective on 

 a coloured plate. 



East of the Salcombe estuary the green schists form the northern 

 and southern fringes of the Metamorphic area, with a considerable 

 tract of mica-schist country between them ; whilst, west of the 

 estuary, the green schists are in the middle and the mica-schists 

 form the outsides. The general strike of the green schist zone, 

 where the two bands coalesce to form one, would seem to be 

 approximately north-west and south-east. This direction is oblique 

 to the general strike of the Devonians on the north, and, taken in 

 conjunction with the fact that the eastern half of the Metamorphic 

 boundary consists of green schists and the western half of mica- 

 schists, seems to point to a considerable difference of orientation 

 in the two systems. Yet the author fails to trace any evidence of 

 pre-Devonian disturbance. 



A detailed description of the structure and petrology of the- 

 mica-schists and green schists follows, and the features of possible 

 resemblance to their presumed analogues in the Devonian rocks are 

 carefully pointed out. With reference to the mica-schist series, 

 he observes that in parts of the district it would be difficult to 

 distinguish the least altered examples of mica-schists, finely inter- 

 laminated quartz-mica-schists, and quartz-schists from examples of 

 the corresponding Devonian sediments. Professor Bonney, he says, 

 has drawn attention to this fact, and ascribes it to the deformation of 

 true schistose character in the former case and to the simulation of 

 schistose character in the latter. There are many valuable petro- 

 logical notes by Mr. Teall relating both to the mica- schist and green 

 schist series. 



Lastly, the author concludes that the only volcanic development 

 in the Devonian area comparable to the green schists is furnished by 

 the Ashprington series. " The correlation between these groups, 

 should the Devonian age of the Metamorphic rocks be established, 

 is, however, less probable than the connection of the green schists 

 with the igneous rocks of Stoke Fleming or with those in the 

 Torcross group" (p. 50). As regards the latter suggestion, we may 

 observe that it accords but doubtfully with the feeble and scattered 

 development of igneous rocks in a group of slates such as that of 

 Torcross, and seems, moreover, in direct contradiction to the strati- 

 graphy as shown in the diagram on p. 62. The advocates of the 

 metamorphism of the Devonian beds had better stick to the Ash- 

 prington volcanic series, the chief difficulty, of course, being to 

 transport it within the Metamorphic area. 



