138 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: 



mosaic. Of this mosaic, which is probably almost all felspar, it should 

 be noted that the coarser part is formed of entirely irregular inter- 

 locking granules ; in the finer part the granules all appear lenticular, 

 and their longer axes conform to the planes of schistosity. 



From M. 9 a coarse gneiss was also noted, and M. 36cl is but a slight 

 variant of M. 36p, 



M. 25c. S. 24° W. Edd., 23 miles is a coarse gneiss with white opaque 

 felspar and grey-green chlorite. 



SCHISTS. 

 MICA SCHIST. 

 354/3/e. Hand Deeps. 



A mica schist in which micaceous layers greatly contorted and con- 

 voluted alternate with granular layers of quartz and garnet. This 

 rock has not been microscopically examined. 



Fig. 1. Mica Schist 

 from Hand Deeps. 



M. 31f. S. 25° W. Edd., 15 miles. 



A grey schist of very fine grain, traversed by rather broad lighter- 

 coloured bands. 



The section shows a distinctly foliated rock, the lighter parts are a 

 clear quartz mosaic ; I can detect no felspar ; the quartz shows numerous 

 fluid inclusions, some with very small bubbles. The darker parts 

 appear to consist of a scaly mica of a yellow tint, associated with 

 which is a little limonite and black granular matter which may be 

 carbonaceous. 

 M. llx. S. 26= W. Edd., 1T8 miles. 



Micaceous schist, the planes of schistosity well marked by lustrous 

 bronze mica, cleaves very perfectly. 



The section shows, in addition to mica, a granular mosaic, which 

 certainly in the main consists of quartz but also contains felspar, which 

 latter can only be detected by its biaxial figure in convergent light. 

 The quartz has, in the larger grains, fluid inclusions with bubbles. The 

 mica is of a rich brown colour, but some few rather well-developed 

 crystals are colourless. The basal sections show numerous acicular 

 microlites, and also very dark brown patches, almost opaque, surround- 

 ing small crystals which are apparently zircon. 



