THE GEOLOGY OF THE ENGLISH CHANNEL. 139 



M. 9c. S. 31° W. Edd., 21-7 miles. 



A schistose rock of light brownish-grey colour and rather pearly 

 lustre ; small darker spots mark an " eye ' structure. 



The general body of the rock is crypto-crystalline, polarizing in low 

 tints. Streams of mica in minutest scales are developed in this 

 ground-mass, especially near the " eyes," which largely consist of this 

 mineral associated with a felspar mosaic in which some granules are 

 large enough for identification. The basal planes of the mica follow 

 one general direction throughout the slide. The dark colour of the 

 " eyes " arises from irregular plates, aggregates of an olive-brown sub- 

 stance with moderate double refraction, but this may be somewhat 

 masked by the colour. 



M. 43a. S. 21° W. Edd., 28 8 miles. 



A thin pebble of dark grey schist. 



A minutely granular rock, consisting of quartz, felspar probably 

 all plagioclase, white mica (sericite), epidote (?), chlorite, and traversed 

 by a vein of calcite. Apatite is present in some quantity. The 

 felspar granules freely exhibit the repeated twinning of plagioclase. 

 M. 20g. S. 25° W. Edd., 20 5 miles. 



Closely resembles M. llx, but the mica has a more decidedly bronze 

 lustre. In both these rocks there are stray features of resemblance to 

 the series from the immediate locality of the Eddy stone. 

 M. 31c. S. 25° W. Edd., 15 miles. 



Eather like a fine-grained granitoid rock, now stained brown by 

 exposure, but fissile from the development of silvery mica along 

 definite planes. 



M. 36c. S. 37° W. Edd., 17-5 miles. 



Largely quartz, but with possibly some felspar, silvery mica chiefly 

 confined to the cleavage planes, which are stained pink with iron oxide. 

 A very fissile rock. 



CHLORITE SCHIST. 

 Off Stoke Point. 



A silvery-green schist, consisting of vivid blue-green chlorite changed 

 here and there to a dull orange, at which places it exhibits a moderate 

 double refraction, and water-clear felspar in which no repeated twins 

 are observable (the section is small). There is also apatite, and much 

 of a granular dusty brown mineral, buff coloured by reflected light, 

 leucoxene. 

 356/1. 4 to 5 miles S. | E. from Prawle Point. 



A chlorite schist with bands of quartz one-eighth of an inch in 

 width. 



