739 



The Algæ -Vegetation of the Caues. 



On almost all the coasts of the Færoes, facing the open sea, 



large or small concealed caves are found, where the sea often 



makes its way far into the rock. In stormy weather, when the sea 



is rough, these caves are more or less filled by the surf rushing in 



Fig. 156. Cave in the rocks facing tlie sea. Illustration from Bordo : Arnefjord. (F. B. phot.) 



with a noise like thunder. Now one might expect to find a luxu- 

 riant littoral algæ vegetation in these caves, which are always fresh 

 and cool, and vs^here there is less danger of the drying process 

 than in the open air. But the dim light is a factor which very soon 

 prevents the greater part of the littoral algæ from thriving here. 

 These algæ are mostly such as seek the light and are accustomed 

 to grow in full daylight. They are therefore only found at the en- 

 trance of these caves, and most of them soon disappear. 



