PHYSICAL GEOGRAPHY 235 



even as late as in the 19th century. Where the hasalt mountains 

 are not too steep nor the mountain-streams too torrential, the flat 

 gravel-cones upon the valley sides, below the notches in the moun- 

 tain, are often overgrown with plants. These gravel -cones often 

 underlie the home-fields of the farmsteads. 



In the fjord districts of Iceland the vegetation upon the basalt 

 mountains differs considerably in passing from the sea inwards. 

 Owing to the effect of the sea-water, the violent storms and the rawness 

 of the climate, the outermost points are comparatively poor in plants, 

 while the vegetation increases inwards towards the valley, and in 

 the bottom of the valleys, especially on the north-western peninsula, 

 remains of coppice woods are often found; but woods could not 

 thrive out along the fjords, still less at the extreme points. Where 

 the basalt does not occur as steep cliffs and is not covered by loose 

 layers of clay, glacial gravel and soil it is usually strewn with loose 

 sharp-edged fragments, split and torn off by frost. The severance 

 of these fragments usually follows the cleavage of the basalt, and 

 they are sometimes slaty and in thin plates, a condition which is 

 especially common in the uppermost part of the basalt formation. 

 Upon the split and torn basalt in the uppermost part of the moun- 

 tains, plants have difficulty in gaining foothold, especially when 

 the climate is as raw and stormy as is the case in Iceland. There- 

 fore, large areas of the higher-lying basalt districts are extremely 

 poor in plant-life even in places, where according to the situation, 

 the conditions might be expected to be somewhat more favourable. 



The landscape in the tuff and breccia districts has a different 

 appearance. Basalt mountains usually have sharp, and breccia 

 mountains soft outlines. Those areas of the cultivated districts and 

 on the lower spurs of the highland w r hich are built up of tuff and 

 breccia have often a more or less undulating appearance; the moun- 

 tains are broken down into numerous rounded ridges and pro- 

 tuberances with intervening stretches of level ground and valleys 

 of irregular shape; but here and there are seen tabular mountains 

 or promontories with steep sides and a flat surface, where the basalt 

 or dolerite has covered and protected the tuff and the breccia. On 

 the plateau, where through centuries storms have been continually 

 altering the sculpture of the surface, the soft tuff-mountains have 

 suffered in particular; here the tuff-ridges are connected into irregular 

 chains which have been eroded in every possible way, and often 

 resemble fantastic ruins with numerous sharp peaks, protuberances 



The Botany of Iceland. I. 16 



