102. Description of the Landes of Acquitania. 
On the plains the most common method consists in planting the 
fir, (Pinus maritimus,) and protecting the young plants by dead 
branches held down by wooden hooks, and climbing and trailing 
plants, as the Clematis, Tamus, Bryonia, &c. 
The maritime fir seems marked by nature as a plant peculiarly 
adapted to break the motions of the sands. Its whirled branches, 
circularly arranged round its firm upright trunk ; its leaves, form- 
ing so many points, exerting great influence, yet offering no resis- 
tance that might be fatal, render it by its whole structure capable 
of resisting the strongest hurricane, and yet of being affected by the 
slightest breeze. The effect which the pine trees have in diminish- 
ing the intensity of storms in mountainous countries has been alrea- 
dy remarked, (Hericart de Thury Journal des Mines, No. 101.) In 
the Alps of Switzerland they are called abrite orage. 
Vines are also planted on these downs. The vine of Rota in 
Andalusia, celebrated for its excellent wine of Tintella, grows on 
the most mobile sands. The oak springs from a soil formed of the 
detritus of a few herbaceous plants, and, supported by the roots of 
the fir tree, soon spreads its lofty branches ; and that part of the 
downs may then be truly considered as secure from the further 
progress of the sands. 
We have been induced to notice thus shortly the means adapted 
to fetter down the sands of the south-west of France, because we 
are aware that in this country the subject has attracted thé atten- 
tion of naturalists, and various methods have been proposed to im- 
pede their progress. Those we have described, present methods 
highly worthy of imitation. Clayonnage is only necessary on the 
extremely mobile summits of the higher downs. But with the ex- 
ception of some sarmentous plants, as the vine, traveller’s joy, &c. 
nothing would prevent the adaptation of the other means,—among 
the most prominent of which is the use of the fir, on whose fertility 
depends the riches of the whole-Landes, and whose products suf- 
fice for the consumption of the whole navy of France. 
The downs of the coast near the basin of Arcachon, lie upon an 
ancient forest of pines. »In some places, and particularly at Cape 
Breton and at Vieux Boucau, volcanic productions are found, 
whose appearance is supposed not to date back more than 30 years, 
(Mag. Encyclop. 8 année T. I.) They consist principally of leucos-. 
tines or volcanic rocks, with feldspathic bases, and pyroxenie or 
augitic rocks, with some specimens of schorl. We observed also 
pumice, basalt, and tufaite. 
Some excellent meadows have been saved from the devastation 
of the sands and sea, by strong dikes. Near them occur leucos- 
tines and phonolites, (clinkstone, Jam.) of a dark black colour, and 
pebbles of quartz and agates. 
Near the Teste there occur some strata of argillaceous ironstone, 
which crop out and show themselves again, about three miles more 
to theseuth-east, at the marsh of Branque Caraon, passing beneath 
downs of 360 feet in elevation.. ya 
