Les Landes

a lowland in southwestern France. It extends 230 km along the Bay of Biscay between the lower courses of the Garonne River (with the Gironde) in the north and the Adour River in the south. It is made up on the surface of layers of quartz sand 20–60 m thick. At a depth of 20–100 cm the quartz sand contains a layer of impervious ferruginous sandstone (hardpan), which promotes the buildup and stagnation of surface water. Les Landes is separated from the sea by a strip of high (to 80–100 m) sand dunes, at the eastern foot of which is a chain of meridionally extending lakes. Until the 19th century the lowland was a vast, very swampy, poorly settled wasteland. Les Landes has pine forests, created by afforestation, and corn fields. There are oil fields (Parentis-en-Born), and resin is extracted.