Such structure could be called a Canyon.
A Canyon
the river running through rock wear it down into deep valley with the steep sides what is it called
Canyon
A deep valley with steep sides would be called a gorge or canyon.
a deep, steep-sided, narrow river valley
A v-shaped valley eroded by a river is called a river valley. This type of valley is characterized by steep sides and a narrow bottom, formed by the erosive action of the river over time.
A valley with very steep sides is called a gorge. These landforms are typically formed by the erosion of water and can vary in size and depth. Gorges often have narrow bottoms and can be found in mountainous regions.
A narrow valley is a V-shaped valley, or river valley. A narrow valley has steep sloped sides that look like the letter V. They are formed by a strong stream.
A rift valley has steep narrow sides and a flat floor. A rift valley forms where the Earth's crust is spreading or splitting apart.
A ravine.
That could be a ravine or a gully
A 'hanging valley' is a valley which is cut across by a river flowing in a deeper valley.