species of marie, the soil is often found only a 
few inches above the limestone ; and its fertility is 
not impaired by the proximity of the rock : though 
in a less absorbent soil, this situation would occa- 
sion barrenness ; and the sandstone and limestone 
hills in Derbyshire and North Wales may be 
easily distinguished at a distance in summer by the 
different tints of the vegetation. The grass on the 
sandstone hills usually appears brown and burnt up ; 
that on the limestone hills, flourishing and green* 
In devoting the different parts of an estate to 
the necessary crops, it is perfectly evident from 
what has been said, that no general principle can 
be laid down, except when all the circumstances 
of the nature, composition, and situation of the 
soil and sub-soil are known. 
The methods of cultivation likewise must be 
different for different soils. The same practice 
which will be excellent in one case may be destruc- 
tive in another. 
Deep ploughing may be a very profitable prac- 
tice in a rich thick soil ; and in a fertile shallow 
soil, situated upon cold clay or sandy sub-soil, it 
may be extremely prejudicial. 
In a moist climate where the quantity of rain 
that falls annually equals from 40 to 60 inches, 
as in Lancashire, Cornwall, and some parts of 
Ireland, a siliceous sandy soil is much more pro- 
ductive than in dry districts ; and in such situa- 
tions, wheat and beans will require a less coherent 
and absorbent soil than in drier situations ; and 
plants having bulbous roots will flourish in a soil 
containing as much as 14 parts out of 15 of sand. 
