VIIl] CULTIVATED LAND: CULTURE ASSOCIATIONS 205 



have been closely observed during a series of years in order 

 to determine the effect of good and bad seasons on the ripening 

 of the grain at or near the upper limit of wheat cultivation. 

 For example, several wheat fields in Derwent dale and in the 

 Hope valley were uncut on October 30th, 1906 ; and, after such 

 a date, wintry types of weather may, in this locality, be expected 

 at any time, and actually came in early November in 1910. 

 It is clear therefore that the wheat fields of the locality in 

 question represent the upper climatic limit of wheat in the 

 Peak District. Generally it is claimed for the vegetation maps 

 of Great Britain that they represent the limits of wheat culti- 

 vation more accurately than has been done on any other maps 

 in any country or at any time ; and, from this point of view 

 alone, the maps are of great value. 



The upper limits of wheat cultivation in the southern 

 Pennines vary somewhat on the diifereht soils. On the 

 eastern plateaux of the Coal-measures, wheat is usually grown 

 up to 700 feet (213 m.), rarely up to 900 feet (274 m.), and 

 most rarely up to 1000 feet (305 m.). On the Pendleside (or 

 Yoredale) shales and river gravels in the Hope and Derwent 

 valleys, wheat is usually grown up to 600 feet (183 m.) and 

 rarely up to 850 feet (259 m.). On the Millstone grit, wheat 

 is rare generally, and has not actually been observed higher 

 than 500 feet (152 m.). On the Mountain Limestone, not a 

 single case of wheat cultivation has been observed. On the 

 other hand, oats (Avena) is not infrequently grown on all the 

 soils up to 1250 feet (381 m.) and more rarely up to 1350 feet 

 (411 m.). Oats are much more commonly grown on the lime- 

 stones than on the sandstones. Cereal crops, other than wheat 

 and oats, are quite rare. Barley (Hordeum) is rarely grown, 

 and rye (Lolium) scarcely at all. In the no-wheat zone, the 

 rotation is of a very primitive character, oats being often 

 grown several years in succession, or, more rarely, in a two- 

 fold rotation with roots, usually turnips (Brassica). In the 

 wheat zone, the usual fourfold rotation — wheat, roots, oats, 

 clover (Trifolium) — is frequently followed. 



From the above facts, it will be seen that wheat is cultivated 

 up to its local climatic limit, but that this varies on the differ- 

 ent soils, being highest on the shales of the Coal-measures 

 and Pendlesides and lowest on the Millstone Grit and the 



