‘The Small Rock:Garden. 129 
suited to the situation ; or the screen or wall may 
itself be slightly curved into an arc, to provide any 
necessary shelter at its extremities. The chief 
difficulty arises in exposed situations where space 
is limited, where there is no room for banks of shrubs 
and trees, or where the expense of their provision is 
too great, and, above all, where powerful west winds 
have to be provided against as well as the north. 
In these instances, or where with free drainage a 
shallow soil is liable to become parched or a retentive 
soil baked by unlimited exposure to the prolonged 
ardour of the sun, a south-east or even east aspect 
is more favourable than one facing full south, and 
therefore the main axis of the rockery should then 
be set due north and south, and fullest protection be 
extended towards the west, advantage being taken, 
in such cases, of any screen existing on the north; 
where space is limited, it is best to build a covering 
wall on the west, and incorporate it in the rockery. 
If the west wind is very powerful and the whole 
site dips towards the west, a trench of fair width and 
from 3ft. to 5ft. in depth, or as deep as is practicable 
consistently with due regard to steepness of slope, 
thickness of soil, adequacy of light, and fitting 
nature of subsoil drainage, should be dug due north 
and south, the material obtained from it being 
banked up on the west side with a covering wall | 
behind if possible. 
The same expedient of making a rockery by 
means of “cuttings” may be adopted on sloping 
ground wherever it seems for any reason desirable ; 
and, indeed, a corresponding system of “banks and 
K 
