Truncated spurs are blunt-ended rock ridges which descend from the steep sides of a U-shaped valley or glacial trough. They are often separated by hanging valleys.
Truncated spurs are classic features of upland glacial erosion. Valley glaciers tend to follow a straighter course than river channels. A valley glacier which formed during the last ice age in an upland area will erode the interlocking spurs of the upper course valley, cutting through the projecting ridges.
Good examples are found in the Langdale Valley in the Lake District, and Devil's Pointn the Cairngorms.