COMMON GANNET. 409 



ture, consisting of trap, intermediate between greenstone and 

 clinkstone, with an uneven fracture, approaching to conchoi- 

 dal, sometimes splintery ; glimmering lustre ; dull brownish- 

 red colour, w^ith specks of dull pale green interspersed ; and 

 small granular structure. It is scratched by the knife Avith- 

 out difficulty, tough and hard under the hammer. The seams 

 have a dark red, rusty appearance, sometimes tinged with 

 dull brownish-black. Felspar and augite are the constituent 

 minerals, the latter in small quantity. The lustre and tex- 

 ture are similar to those of the rock of North Berwick Law', 

 but the colour of the latter is greenish-grey, with interspersed 

 patches of reddish-brown. 



Although a great portion of the upper surface of the island 

 is composed of rock, there is an abundant vegetation, consist- 

 ing chiefly of Festuca ovina, F. duriuscula, and a few other 

 grasses, mixed with plants usually found in maritime situa- 

 tions. Among other species, the following were observed by 

 me : — Silene maritima, Cochlearia officinalis, Plantago Coro- 

 nopus. Lychnis dioica. Geranium molle, Statice Armeria, 

 Drabaverna, Urtica dioica, Rumex crispus,Sonchus oleraceus, 

 Leontodon Taraxacum, Vicia lathyroides, Viola canina, Bellis 

 perennis, Lycopsis arvensis, Myosotis collina, Cerastium semi- 

 decandrum, Luzula campestris, Bromus mollis, Aii*a prtecox, 

 and, lastly, Lavatera arborea and Beta maritima, the two 

 latter growing in great abundance among the ruins, which 

 harbour great numbers of Helix aspersa. 



But the circumstance connected with the Bass most inte- 

 resting to the zoologist, is its being one of the few places in 

 Britain to which the Gannet resorts during the breeding- 

 season. The number Avhich I saw on the 13th May 1831, 

 when I for the first time visited it along with some friends, 

 might be estimated at twenty thousand. Every part of the 

 mural faces of the rock, especially towards their summits, was 

 more or less covered by them. In one spot near the landing- 

 place, about forty yards in circumference, and on a gentle 

 slope of gravelly ground, about three hundred individuals 

 were sitting in peaceful security on their nests. 



The Gannets arrive about the middle of February or the 

 beginning of March, and depart in October ; some years, a 



