We study the final architecture of planetary systems that evolve under the combined effects of planet-planet and planetesimal scattering .
Using N-body simulations we investigate the dynamics of marginally unstable systems of gas and ice giants both in isolation and when the planets form interior to a planetesimal belt .
The unstable isolated systems evolve under planet-planet scattering to yield an eccentricity distribution that matches that observed for extrasolar planets .
When planetesimals are included the outcome depends upon the total mass of the planets .
For M _ { tot } \gtrsim 1 M _ { J } the final eccentricity distribution remains broad , whereas for M _ { tot } \lesssim 1 M _ { J } a combination of divergent orbital evolution and recircularization of scattered planets results in a preponderance of nearly circular final orbits .
We also study the fate of marginally stable multiple planet systems in the presence of planetesimal disks , and find that for high planet masses the majority of such systems evolve into resonance .
A significant fraction lead to resonant chains that are planetary analogs of Jupiter ’ s Galilean satellites .
We predict that a transition from eccentric to near-circular orbits will be observed once extrasolar planet surveys detect sub-Jovian mass planets at orbital radii of a \simeq 5 - 10 { AU } .