Occur in a river's upper course, where vertical erosion is the dominant force in determining the river's course.
1. In upland areas, small streams begin to develop and erode the landscape.
2. The stream cuts vertically down the landscape.
3. A small v shaped valley is cut. Vertical erosion creates a narrow valler.
4. New slopes are created,
5. The edges of the new hill slopes are called spurs. They line up one after the other.