ON THE METAMORPHIC ROCKS OF SOUTH DEVON. 715 



50. Notes on the Metamorphic Bocks of South Devon. 

 By Catherine A. Eaisin, B.Sc. (Read June 23, 1887.) 



(Communicated by Prof. T. G-. Bonney, D.Sc, LL.D., F.E.S., F.G-.S.) 



Contents. 



I. Boundary of Slaty and Metam Or- 

 phic Series. 



1. Hope Cove. 



2. West of Salcombe Estuary. 



3. East of Salcombe Estuary. 

 . Southward of South Pool. 



5. Eastward of Estuary ; inland, 



and Hall Sands. 

 II. Microscope Slides and Lithologi- 



cal Characters of Metamorphic 



Eocks. 

 A. Microscope Slides. 



1. Chlorite-Sehists. 



2. Micaceo-cbloritic Schists. 



3. Mica-Sehists. 



B. Macroscopic Struetures. 



1. In Mica- and Micaceo-chloritic 



Schists. Strain-slip cleavage. 



2. In Chlorite-Sehists. 



III. Stratigraphical succession in Me- 



tamorphic rocks from their 

 northern limit. 



1. (a) Interbanded Series. 

 (b) Chlorite-Schist. 



2. (a) Mica-Schist. 

 (&) Interban dings ? 



3. Mica-Schist. 



Estuary south of South Pool. 

 Eastward of South Pool. 



IV. Summary. 



There are scanty notices, by De la Beche and other earlier writers^ 

 of this southernmost part of Devonshire ; but later it has been very 

 fully described by Professor Bonney * ; and taking his paper as a 

 guide, I was able during two visits to obtain some knowledge of the 

 district. I have ventured to think that a few supplementary details 

 might be of some slight interest. 



I. BOUNDARY OE SLATY AND METAMORPHIC SERIES. 



As I had not time to visit thoroughly all parts of the district, I 

 tried primarily to make an examination of the exposures in the 

 vicinity of the junction of the slaty and the metamorphic series. 

 Here I was anxious to arrive independently at a conclusion on the 

 question whether metamorphism had affected a continuous series 

 of beds, or whether the southern rocks had the character of a sepa- 

 rate and probably much older formation. Hence, before visiting any 

 of the sections already described, I made expeditions to two localities 

 on the shores of the estuary north of Portlemouth, where I found 

 exposures, in one place quite, in the other nearly, continuous from 

 Devonian to metamorphic rocks. I had no real difficulty in deciding 

 when I had passed from one formation to the other, and the opinion 

 then formed as to the complete distinctness of the two series was 

 confirmed by further examination in the field and by the microscope. 



Along the southern boundary of the slaty rocks, I visited the cliff 

 exposures of the eastern and western coasts, those bordering the 

 estuary, and I also zigzagged across parts of the intervening country. 



1. Hope Cove. — The western limit of the boundary line at Hope 

 village is marked on the Survey map, and has been described by 

 * Quart. Journ. Geol. Soc. vol. xl. p. I, 



3 c2 



