hanging valley 
noun
A valley which is cut across by a deeper valley or a cliff.When it rains here, waterfalls pour off hanging valleys, and the muddy river tears into its banks and dumps loads of sediment at each bend....
- The highest mountains were cloaked in mantles of snow and ice with glaciers perched in the hanging valleys as though suspended by some invisible thread from the summits.
- Milford Sound is a 13-mile-long fiord decorated by glaciated hanging valleys, many ‘bridal-veil’ falls and the snowcapped, 5560-foot Mitre Peak, a region hard to surpass for its natural beauty.