A stream with a dendritic drainage pattern, for example, can be subject to slow tectonic uplift.
However, as the uplift occurs, the stream erodes through the rising ridge to form a steep-walled gorge.
[1] A superimposed stream is a stream that forms over horizontal beds that overlie folded and faulted rock with varying resistance.
Having cut down through the horizontal beds, the stream retains its course and pattern as it proceeds to erode the underlying rocks despite their different character.
The stream erodes a gorge in the resistant bed and continues its flow as before.