One of the interesting aspects of transitional and turbulent boundary layers is the development of counter‐rotating streamwise vortices near the wall. The most regular pattern is found in a boundary layer on a concave wall where the generation mechanism is known to be the Go¨rtler instability. The origin of these vortices in other translational and turbulent boundary layers is presently unknown. Since the counter‐rotating vortices are located in a region of strong shear, low‐speed fluid is pumped away from the wall which coalesces into regions of low momentum lying between the vortices. As this pumping action continues, localized inflectional velocity profiles become apparent in the transitional and turbulent boundary layers. The oscillations which develop upon these profiles scale with the local thickness and velocity difference in the same manner as the two‐dimensional steady free shear layer stability problems. The oscillations grow to large amplitude and break down into new turbulence in both the transitional and turbulent boundary layers.