Le Sahara

Le Sahara by E. F. Gautier is a scientific study written in the early 20th century. It synthesizes exploration records and modern science to explain the Sahara’s physical geography—its structure, climate, landforms, flora and fauna—and what these mean for human habitation. The work emphasizes deserts as climatic phenomena, the interaction of wind and water in shaping the land, and the Sahara’s role as a vast barrier between Mediterranean North Africa and the Sudanic south. The opening of the book sketches how the desert came to be known, then lays out why it exists where it does: latitude-linked high-pressure belts over the Atlantic, low relief and coastlines aligned with latitude, and limited mountain barriers intensify aridity. It describes the region’s geology as an ancient continental “shield” capped in places by younger sediments and punctuated by volcanic massifs, with relief organized along broad east–west and north–south fault trends. Climate is defined by extreme dryness, sharp temperature swings, powerful dusty winds (including regional variants like sirocco and khamsin), highly irregular cloudbursts that do the real hydrologic work, and the adaptive strategies of sparse plants and animals; human presence is thin and concentrated in oases, and the desert forms a historical divide between Maghreb and Sudan. The text then sets the rules of desert landforming: endorheic basins, vast gravel plains (reg/serir), rock tables (hamadas), and dunes (ergs) whose shapes and stability reflect underlying fluvial topography; it stresses the joint roles of water and wind, the sorting of sands, and protective crusts that limit deflation. Finally, it turns to the past, arguing for the desert’s great antiquity (even petrified ancient ergs), while highlighting a wetter Quaternary phase when large rivers radiated from the Hoggar toward the Niger and the chotts, leaving fish, crocodile, and other tropical relics—yet still ending in closed basins rather than the sea.