Valleys

Named river and glacially carved valleys, dales, dells and glens, the broad lowland corridors erosion cuts between higher ground, following the fluvial and glacial valley classes of standard geomorphology. Includes river valleys named for the waterway or district that shaped them (Emmental, Colne Valley, Sacred Valley), valleys still bearing the U-shaped cross-section of past glacial carving (Hetch Hetchy, Alpine Rhine Valley), and broad valleys studded with erosional remnants (Monument Valley). Belongs here: any open, broadly sided lowland corridor between higher ground. Does not belong here: a valley whose walls are markedly steep and narrow enough to be known as a canyon or gorge (Gorges and Canyons), a valley of tectonic rift origin (Structural and Tectonic Formations), or a valley still occupied by active glacial ice (Glaciers and Ice Formations).