BRITAIN 301 



sedges and cotton-grass. Heather is usually associated 

 with this kind of vegetation, which is extensively de- 

 veloped in the west and north of Britain and on the 

 uplands and highlands : heavy and impervious infertile 

 glacial clays are particularly favourable to their forma- 

 tion. In many cases the peat has taken the place of 

 forests, as is shown by the remains of trees found buried 

 in the high moors. 



Another kind of moor, characteristic of the lowlands, 

 is the fen, low, or meadow-moor which usually takes 

 the form of reed (rush or sedge) or grass marsh. It 

 is frequently associated with alluvial tracts, in process of 

 formation, undrained, and provided with water rich in 

 lime or organic deposits, such as the ' fens ' or ' carses ', 

 which are represented across the Channel by the ' moeres ' 

 and ' polders ' of Flanders and Holland. When they are 

 drained and cultivated, the peat decomposes into a rich 

 black earth which is especially suitable for market 

 gardening. 



The older rocks, which form so large a proportion of 

 the uplands and highlands of Britain are, on the whole } 

 of an infertile nature. This, added to the uncertainty 

 of the weather and the difficulties of cultivation, renders 

 them more suitable for pastures. It was largely the 

 nature of the soil which determined the fate of the hills, 

 after they were cleared of their timber, the poorer soils 

 rapidly developing moors, dry grass-moors, heath-moors, 

 &c., the better kinds giving rise to pastures. Among 

 the best for pastures, under the moist and equable 

 climate of Britain, may be mentioned the limestone soils 

 of Yorkshire, Sutherland, &c. 



