98 Description of the Landes of Acquitania. 
pends upon whether or not they are affected by the tides. That of: 
the basin of Arcachon is entirely marine: its sides are seldom wood-. 
ed. Occasional hedges of the Tamarix Gallica are met with, and 
the shores are strewed with great quantities of Zostera marina. 
The borders of other lagunz are oftentimes clothed with extensive 
woods, and we have had occasion to allude to the nature of their- 
preductions before. In the ponds neighbouring the sea, we meet. 
with the Conferva capillaris, C. catenata, C. glomerata, Ulva com- 
pressa, U. Linza, U. intestinalis, Riccia minima, Lemna trisulea, 
Chara flexilis, Menyanthis trifoliata, (only at the laguna of Sous- 
tons,) Alisma Plantago, A. natans, A. ranunculoides, A. Damaso-. 
nium, Marsilea quadrifolia, Nymphza lutea, N. alba, Typha lati- 
folia, T. angustifolia, several species of Potamogeton, &c. On the 
borders of the lagunz, Hottonia palustris, Convolvulus soldanella, 
Acorus calamus, Epilobium palustre, Hibiscus palustris, Sonchus 
palustris. A boggy, peat soil is formed by the Myrica Gale, Sphag- 
num palustre, Anthericum ossifragum, Cineraria palustris, Narcis- 
sus Pseudo-Narcissus, N. Tazzetta, Lythrum salicaria, Hyperi- 
cum hircinum, Hieracium paludosum, Gnaphalium uliginosum,. 
Serapias longifolia, Equisetum palustre, E. eburneum, &c. In the 
saline marshes, Hippurus vulgaris, Salicornia fruticosa, &e. In 
moist, shady spots, Viburnum opulus, V. tinus, Narcissus Jon- 
quilla, Anthoceros levis, A. punctatus, Marchantia stellata, M. 
umbellata Scop., Targionia hypophylla. The banks of the Adour 
present some plants of interest. Among them, Salix purpurea, 
S. fragilis, Myagrum perfoliatum, Trifolium strictum, Inula puli- 
caria, Fraxinus excelsior, &c. t f 
The downs and hills of sand which line the coast, and retain the 
waters of the lagunz, whose forms and situation are constantly mo- 
dulated by their motions, demand our next attention. | 
The general direction of the currents i the Bay of Biscay is 
from north to south, or sweeping down the basin. The coast is. 
every where level and continuous, presenting a sterile and epen 
shore,—a certain indication of little depth of water for a great dis- 
tance ; yet on few shores is the action of water more violent, rising 
even at ordinary tides with great fury, throwing to a great distance. - 
on the shore the wrecks of ships, or the trunks of pine trees long 
buffeted by the wind. 
Sometimes specimens of shells and plants from the tropics are 
stranded on these shores ; but excepting a few species, principally 
belonging to the genera Mactra, Venus, Unio, Solen, Telliaa, 
Strombus, Murex, Pecten, Ostrea, Anomia, Ortygia, Buccinum, 
and Voluta, and a few pebbles thrown up by the tide, generally. 
quartzose, sometimes hydrated, offering varieties of chalcedony, jas-. 
per, and agate, no quantity of organic or inorganic substances is: 
thrown up, along the whole line of the shore, to disturb the uni- 
formity of that deep, oceanic bed of sand, which seems to be brought. 
up from its home to cover the surface of the earth. As the tide, 
recedes, these sands (more especially in the summer season) become 
