XIV. 
Pickering on the north ; eastward they run out to the bold promontory 
of Flamborough Head, and south-eastward sink below the levels of 
Holderness. Their surface is agreeably undulated by a complication of 
bold rounded hills, ramified between the smoothly excavated valleys, 
down which no water ever ran, though their gently inclined surface and 
sinuous course mark clearly the powerful and gradual action of water. 
In some localities (as Thixendale) many of these valleys come together, 
and produce the extreme of gentle and pleasing undulation. Copious 
springs of pure water issue from the foot of the Wolds. 
Internal Structure. — At a few inches or feet in depth from the 
surface, chalk (with few flints) is almost uniformly found ; in some 
of the valleys, however, (as about Givendale) lias clays appear ; in 
others (Middleton) gravel abounds. The soil, which on this calcareous 
rock might be expected to be pure calcareous earth, contains commonly 
an admixture of sand, and sometimes of gravel. 
Aspect of Vegetation. — Chalk hills are generally devoid of trees, 
except where much gravel, sand, or clay, covers locally the calcareous 
rock : this happens in Oxfordshire, but not in Yorkshire, except on the 
eastern and lower part of the Wolds. The high western border is as 
bare in Yorkshire as in Wiltshire ; and could we restore (as perhaps 
even agriculturists might vainly desire) the rich short carpet of unfading 
green, which preceded artificial crops on these hills, the resemblance 
between the Yorkshire Wolds and Wiltshire Downs would be as perfect 
as when Lister remarked their similarity. Water meadows are not so 
frequent in Yorkshire as in Wilts and Dorset ; though in some instances 
the springs which gush out from the Wolds might suffice for irrigation 
to a considerable extent. 
DISTRIBUTION OF PARTICULAR PLANTS. 
The peculiarity of chalky soils is so marked, that it appears sur- 
prising to find only one plant exclusively in the Wold district of York- 
shire ; this plant is Crepis biennis. Perhaps the frequency of sandy 
and gravelly soils on the surface of the chalk rock, the dryness of the 
valleys, and the general scantiness of the herbage, may be among the 
reasons for this want of botanical peculiarity. 
