GEOLOGY OF SCILLY. 241 



The rock itself is not always confined to the constitu- 

 ent parts of quartz, felspar, and mica : schorl is a very 

 common ingredient, sometimes accompanying the mica, 

 sometimes replacing it. Hornblende is rare, chlorite 

 still rarer. Veins of pure white quartz, of considerable 

 size, often intersect the granite ; rose-coloured quartz, 

 and even chalcedony, have been found ; but the general 

 natm^e of the stone is of a coarse kind, useless for 

 quarrying ; and the granite needed for the new light- 

 house is brought from Cornwall. 



The reader will be curious to know about the zoolo- 

 gical wealth of Scilly. Eich the place undoubtedly is, 

 yet not so rich as I anticipated. When Dr Acland, of 

 whom Oxford is justly proud, commenced the founda- 

 tion of that anatomical museum over which he pre- 

 sides, Scilly was the first place chosen by him for the 

 collection of specimens, on account of its geographical 

 position at the entrance of the Bristol, Irish, and Eno-- 

 lish Channels, with Eennel's Current near. He em- 

 ployed Victor Carus, since known by an excellent work 

 on Morphology,'-' as his purveyor for six months, ex- 

 ploring and dredging. Carus has contributed a little 

 paper to North's Week at Scilhj, in which he gives 

 expression to his opinion that the " sea is not a dense 

 one, although there are multitudes of zoophytes and 

 hosts of fishes ; there are only a few molluscs, some 

 worms, and a not very large number of echinoderms." 

 On the whole, he does not think Scilly equal to the 

 Channel Islands. Either I have been lucky, or my 



* System der thierischen Morphologie. 1853. 



Q 



