H4 The bish Naturalist. March, 



sharp east and west folds, and dip at high angles. This is 

 accountable for the low rounded ridges of rock that every- 

 where traverse the island east and west, and in some places 

 cause the surface to strikingly resemble a sheet of corrugated 

 iron. A series of very strong vertical joint-planes and faults 

 traverses the beds north-west and south-east, and much affects 

 the modelling of the island. The main valleys are cut along 

 these lines, and at the west end some magnificent vertical 

 cliff walls have the same origin. Another result of geological 

 conditions is the presence of innumerable caves, often of con- 

 siderable length, cut both along the strike and along the joints 

 referred to. In two cases these open by funnels on the top of 

 the cliffs at quite a distance from the sea margin. Drift is 

 almost completely absent, only a couple of small patches 

 having been observed, but the disintegration of the slates has 

 produced a light rich soil in places. There are several little 

 streams, with quite a luxuriant vegetation along them, and 

 several tiny boggy lakelets. Cultivation is confined to two 

 areas in the south and east, in the two main valleys, but does 

 not include more than perhaps one-twentieth part of the 

 island. Here are grown excellent potatoes and oats, and some 

 rye, barley, cabbages, turnips, and beet. The major part of 

 the surface of the island consists of green, grassy, rocky heath, 

 furnishing excellent pasturage. By farming and fishing a 

 present population of 23 families is supported. 



Character of the Vegetation. 



From the point of view of vegetation, the surface of the 

 island is easily and naturally divided into three areas, namely 

 — the cultivated area (which includes the most sheltered por- 

 tions of the island and the deepest soil, and was originally, no 

 doubt, largely occupied by arbuscular vegetation, which has 

 still its headquarters there), the heath area (which spreads over 

 the greater part of the island), and the maritime area (which, 

 owing to the extreme exposure and the large area subject to 

 soakings of salt spray, is more extensive than the bold eleva- 

 tion of the island would lead one to expect). 



The Cultivated Area, — The tilled land, which covers two 

 irregular areas about the " villages " of Garranty and Craggy 



