974 



slope or »Brække« (see Fig. 181). On the lower part of a moun- 

 tain, tilis development has generally proceeded so far thai the per- 

 pendicular scarps are entirely ohliterated, the narrow »Brækker« 

 run into each other, and a broad typical slope or »Li« results. 



The vertical escarpment with its cracks and small ledges is 

 the home of the cliff vegetation. . The »Brække« and its modifica- 

 tions have so much loose soil that other plant-associations take 

 possession. It will now be evident, that a mountain-terrace vsåth 

 some loose soil and favourably situated as regards moisture and 

 insolation may become a habitat which offers greater advantages 

 lo piants than the grass-slope (compare p. 963), and is, relatively 

 speaking, a »forcing bed«. 



Another type of cliff-formation is that popularly known as 

 »Gjov« (gorge, ravine or cove). By »Gjov« (see Fig. 183) we under- 

 stand a great mountain cleft or ravine, often of considerable lenglh 

 and so roomy that people may journey in it; the water which 

 trickles from the rock-springs frequently forms a streamlet which 

 flows along the bottom. The sides of the »Gjov« may be regarded 

 as two »Hamre« parallel to each other and at no great distance 

 apart. It is characteristic of a »Gjov« that the position of its walls 

 checks excessive insolation and drought, hence particularly favour- 

 able conditions may be offered to vegetation, except that in piaces 

 it may be too dark and too moist. It is well known in the Færoes 

 that the »Hamre« and the »Gjove« are just the piaces where vege- 

 tation developes with the greatest luxuriance. Here again we ma}' 

 recall what has been already pointed out, and is confirmed by 

 Oettli (see 5" on p. 972), that these piaces are specially favoured 

 because inaccessible to sheep and their grazing. 



From a botanical point of view the »Hamre« (rock-ledges) and 

 the sides of »Gjove« (ravines) may be considered together as one 

 group which may be subdivided according to light, exposure and 

 humidity. We have found the following subdivisions suitable : 



(1) the sombre and humid »Gjov«-side of a narrow ravine. 



If the ravine is sufficiently wide, so that the illumination is 

 favourable, its sides may be regarded as »Hamre«, which may be 

 grouped under one of the following: 



(2) the humid, north-exposed »Hammer« or »Gjov«-side, 



(3) the semi-humid, usually south exposed »Hammer« or »Gjov«- 



side, and 



