4 VEGETATION OF THE PEAK DISTRICT [CH. 



The hill slopes of the Coal-measures are rarely very steep, 

 and are characterized by a number of typical oak (Quercus 

 sessiliflora) woods which are at least semi-primitive in character. 

 These woods occasionally spread out for a little distance on to 

 the low, flat or gently sloping plateaux. The valley bottoms 

 are almost filled up with overgrown, manufacturing villages, 

 many of which have a population of twenty thousand people. 

 The smoke from the villages and hamlets, for even every 

 hamlet has its factory, frequently renders the sky dull and 

 the atmosphere thick and heavy. Sandstone walls as a rule, 

 hedgerows occasionally, separate the cultivated fields ; and the 

 stone walls and the tree trunks are permanently blackened with 

 soot and smoke which have effectually destroyed almost all 

 traces of mural plants, especially Cryptogams. Only in the 

 heart of the woods, some of which retain their original sylvan 

 character, may one, in this Coal-measure country, forget the 

 propinquity of coal-mines and mills. 



The higher hills of the central massif consist of sandstones 

 and shales belonging to the Millstone Grit and to the Yoredale 

 or Pendleside (Hind, 1897, etc.; Hind and Howe, 1901) series of 

 rocks. Here there are fewer factories than on the Coal-measures, 

 and no coal-pits. The higher hill summits are unpopulated, 

 and covered with peat moors. Here and there, the moorland 

 plateaux terminate abruptly in precipitous escarpments, locally 

 known as "edges," formed of massive sandstone rocks. The 

 larger and broader valleys are known as "dales," the smaller 

 and narrower ones as " cloughs " or " deans," or, further north, 

 as " ghylls." The upland valleys shelter woods of oak (Quercus 

 sessiliflora), and rarely of birch (Betula pubescens) ; but more 

 frequently the slopes of the steep valleys are tenanted by 

 scrub or grassland. The bracken is a characteristic plant of 

 the drier slopes. The upper portions of the cloughs contain 

 numerous reservoirs (see figure 36) which are fed by the 

 streams issuing from the peat moors of the plateaux. The 

 lower plateaux and valleys are cultivated, chiefly as perma- 

 nent pasture: arable land is decidedly scarce: wheat, in 

 particular, is very rarely grown; and even fields of oats are 

 uncommon. The fields are usually separated by sandstone 

 walls; though, as in the Coal-measure country, hedgerows 

 occur where the shales are of great extent. 



