basin and range

A landscape of parallel mountain ranges separated by flat desert valleys — the defining topography of the interior American West from eastern California to central Utah, and from southern Idaho to northern Mexico. The ranges are horsts; the valleys are grabens. The earth's crust is stretching, pulling apart, and the landscape is cracking into long, north-south strips of mountain and basin, mountain and basin, repeated for a thousand miles. The phrase names both the landform and the geological province.