Truncated Spur

A truncated spur is a ridge that descends from higher ground toward a valley floor or coastline and ends abruptly in a steep, inverted V shaped face. It forms where a glacier has advanced through a valley that originally curved around a series of interlocking ridges shaped by a meandering river. Because a glacier cannot bend around these ridges as easily as flowing water, it erodes straight through their protruding tips by abrasion and plucking, cutting them off into steep cliff like faces. Truncated spurs commonly flank glaciated valleys, and waterfalls often appear where a hanging valley between two truncated spurs drops into the main valley below, as at Yosemite National Park.