298 A FOREST TOUR AMONG THE DUNES OF GASCONY. 
13 lbs. of seed being used per acre. This plant, which is a kind of 
grass,! with an underground stem and strong interlacing side-roots, 
has a remarkable power of keeping its head growing above the 
surface of the rising mound, the particles composing which are held 
firmly together by it. The sand subsequently left by the tide, either 
travels along the shore, or is taken up again by the sea and 
deposited elsewhere. An artificial dune, constructed in the manner 
above described, now extends along the coast for a distance of 125 
miles, from the Gironde to the Adour. 
As soon as the further importation of sand over the country has 
been arrested by the palisade, and the covering of the future planta- 
tions has thus been guarded against, the sowing of the ground in 
rear of it is at once undertaken. ‘This is effected in successive 
parallel belts of about 20 yds. wide, commenced at a distance of 
5 yds. from the line to which the inner slope of the dune will 
attain when it is completed. By beginning at this point, and 
working gradually away from the sea, the plantations are secured 
against injury by sand which has already passed the line of the 
barrier. If the sowings were begun elsewhere, they would soon be 
covered by the advance of the naturally-formed dunes over them. 
The land to be operated upon is roughly levelled, and a mixture 
consisting of 11 lbs. of pine seed, 7 lbs. of broom seed, and 5 lbs. 
of gourbet per acre, is then sown on it broadcast, a palisade being 
erected at its inner limit, so as to prevent the seed from becoming 
buried under sand, carried over it by land breezes ; this structure is 
moved back as the work progresses, so as to serve for the protection 
of other belts, as the sowing of each is in its turn undertaken. The 
sowings are carried on from October to May. The seeds are covered 
with branches and brushwood, laid like tiles or thatch, with their 
butt-ends towards the sea, and kept down by means of sand thrown 
upon them. The surface is thus temporarily protected, until the 
plants have had time to grow up and take hold of the soil. If the 
covering of branches is at any time disturbed by the wind, they 
must be at once readjusted; and should it be found that any 
damage has been done to the seeds or seedlings, the ground must 
be re-sown and re-covered with branches. The cost of the entire 
work is said to amount to about £8 per acre. We unfortunately 
did not see it in progress, but we saw some ground that had 
recently been treated in the manner described. 
We visited the artificial dune of St. Eulalie—Mimizan, which is 
1 Syn. Psamma arenaria, Hooker. 
