The stability of a geostrophic frontal current of constant slope over a stratified ocean is investigated using asymptotic techniques for large horizontal wavenumber and a small Burger number. The front is called canonical because it should approximate the edges of eddies or boundary currents. Results show that the front is unstable for an along the front wavenumber greater than f/V0 where V0 is the current velocity. But the instability is confined to a region near the vertex of the front of horizontal extent 0(V0/f). The flow becomes more unstable for increasing wavenumber and it is speculated that this region near the vertex will be strongly mixed, rounding off the sharp vertex of the steady state flow. There will be strong internal wave propagation from the interface of this region into the ocean when the frequency is greater than f.