vill] 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 different 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 (805 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 (881 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 (Loliwm) 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 (T'rifolium)—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 
