86 J. H. MAIDEN, 
though part of it filters through the interstices between the planks, 
and forms a steep slope to the leeward, which serves as a support — 
to the planks. The sand now gradually mounts up,.and when 
nearly flush with the top of the palisade, the latter is levered up 
some 24 inches. This process is continued until the dune is some 
25 to 30 feet high, when a cordon of faggots is planted on the 
summit of the dune just to windward of the palisade. The palisade 
is now left in this last position until a third fence, which has been 
erected some 5 or 6 feet to the east of the leeward slope, is over- 
topped, and the base of the dune is increased without affecting 
the height by the sand blowing over the tops of the palisade and 
cordon. When this fence is covered, the palisade is moved back 
a few feet, and the sand coming over the tops of the cordon faggots 
fills in the space between them and the palisade. The latter is 
then again levered up, and the process continued until the dune 
assumes the final profile required. The formation of the artificia] 
dune usually requires a period of from 15 to 18 years. ‘The growth 
is naturally irregular, being dependent on the season. Steady 
strong winds are the most favourable. On the completion of the 
dune the surface is consolidated by half burying, in a vertical 
position, faggots composed usually of pine branches. These faggots 
have usually a circumference of some 14 to 16 inches and a length 
of 30 inches, and are planted some 14 to 16 inches apart. Between 
these faggots is sown the seed of the “Gourbet” or “ Marram 
Grass” (Ammophila arundinacea, Host.) in quantity about |3jibs. 
to the acre. The consolidation is naturally only requisite on the 
summit and windward slope.' 
Schlich* describes a somewhat simpler method of con- 
structing the dune littorale :— 
“Although air currents are capable of moving the sand along 
level and gently sloping ground, they cannot lift it above a certain 
height. Hence it is necessary at a moderate distance (100 — 300 
1 McNaughton, C. B., ‘‘The sand-dunes of Gascony,”—Agricultural 
Journal (Capetown), 7th February, 1895. A valuable and exhaustive 
paper. o ares Serene 
.* Manual of Forestry, Vol. 11., p. 34; see also 1v., 524. 
