142 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : 



The serpentine, some of which is colourless, splits up under crossed 

 nicols into doubly refracting bands and isotropic portions. 



The association of felspar with a massive serpentine is rare, but 

 Professor Bonney has recorded an instance from the Lizard district. 



This specimen acquires some value, despite its small size, since in 

 Hunt's series there occurs a serpentine boulder, H. 6, of 5 cwt. 



QUARTZITES. 



A number of quartzites, very similar to some in the Budleigh 

 pebble-bed, have been dredged from a great many stations. Up to 

 the present no fossils have been found in them. These rocks vary in 

 colour, being purple, red, light red, buff', grey and white, and are 

 associated with very hard grits which have not been sufficiently 

 examined. 



M. 80. S. 16f W. Edd., 48-9 miles. 



Purple quartzite, very compact in structure. Quartz grains, sub- 

 angular and of very uniform size, fluid enclosures common. The 

 cementing material silica with much iron oxide ; this cement appears 

 to be minutely granular. An occasional quartz grain shows hair-like 

 microlites. 



This may be taken as a type. Other Puiyle Quartzites were dredged 

 at Stations M. 31, M. 36, M. 13, M. 35, M. 27, M. 26, M. 34, M. 29, M. 14, 

 M. 20, M. 9, M. 40, M. 22, M. 25, M. 43, M. 50, M. 67, and M. 80. 



Red quartzites from M. 11, M. 72. 



Light red quartzites from M. 13., M. 30. 



Buff quartzites from M. 34, M. 20, M. 22, M. 41, M. 43. 



White quartzite from M. 21. 



M. llf. S. 26° W. Edd., 17-8 miles. 

 A grey grit. 

 A little mica appears in the section. The rock is practically a quartzite. 



SEDIMENTARY ROCKS. 



Under the heading of sedimentary rocks have been included all 

 altered varieties, except such as may possibly have been fully meta- 

 morphosed to schists and quartzites. 



CARBONIFEROUS AND EARLIER. 

 SANDSTONES AND GRITS. 

 354/4k. 6^ miles W. from Rame Head. 



A red micaceous grit, probably Devonian. 

 M. 9b. S. 31° W. Edd., 217 miles. 



A light brown sandstone of flaggy structure, bedding marked by 

 slight variations of tint. Possibly Devonian. 



