THE GEOLOGY OF THE ENGLISH CHANNEL. 127 



but otherwise much clouded, and all are plagioclases. The quartz 

 contains small and moderately numerous fluid inclusions. Hornblende 

 occurs in two forms ; some of it is almost certainly an original mineral, 

 and shows good basal sections, with inclusions, however, of other 

 minerals. Elsewhere the hornblende is more fibrous. The mica has 

 suffered considerable change, if I am right in so identifying a very 

 doubtful mineral, and very little unaltered augite remains. Might 

 almost equally well be classed as a quartz aphanite. 



M. 9e. S. 31° W. Edd., 217 miles. 



Dark grey crystalline rock of rather fine texture. Small felspars of 

 irregular shape and slightly greenish tint, small quartz granules, very 

 clear and bright. 



The felspars are plagioclase, much clouded in the centre, quite clear 

 around the margins when crystal outline is shown. Some have obviously 

 been broken. In the felspars occur very numerous small prisms and 

 acicular forms of a clear mineral which may be zoisite. Some felspars 

 show an irregular zone of decomposition products a little within the 

 margin. Most of the quartz areas break down in some part to a 

 mosaic of interlocked granules. The quartz contains fluid inclusions. 

 Strain shadows show in both quartz and felspar. Hornblende, chiefly 

 of an olive shade, is freely developed, much is markedly uralitic. A 

 little chlorite occurs. There is some apatite, and a little ilmenite. 



M. 9r. (Same location as last.) 



Fine-grained grey rock, felspar and hornblende visible. 



Plagioclase felspar, somewhat clouded, occasionally achieving good 

 crystal boundaries, and with a marked tendency to zoning from 

 secondary growth, clearer from decomposition than the centres. Ee- 

 peated twins somewhat frequent. Minute epidote has been freely 

 developed in many of the felspars, and granules of a mineral which is 

 apparently epidote. Fibrous hornblende is a prominent constituent, 

 occurring in large patches, spreading and extending between the 

 felspar areas ; principally it is of a green colour with a tendency to 

 blue ; here and there brown and olive shades occur, especially in the 

 interior of some of the larger patches. Quartz is fairly plentiful, with 

 numerous small fluid inclusions, most with bubbles, and a few 

 apparently include very small cubic crystals. Some apatite. 



M. 19a. S. 28° W. Edd., 23-3 miles. 



Dark greenish grey, granular crystalline. Felspars small and 

 slightly green in tint. Fine grain. Texture micro-granitic. Tlie 

 felspars a good deal clouded with pale brown decomposition products, 

 but with frequent clear patches. Some crystals with characteristic 



