Constraints and time evolution in generic <i>f</i>(Riemann) gravity

We give a detailed canonical analysis of the n-dimensional f(Riemann) gravity, correcting the earlier results in the literature. We also write the field equations in the Fischer-Marsden form which is amenable to identifying the non-stationary energy on a spacelike hypersurface. We give pure R-2 and R mu nu R mu nu theories as examples.