Counterterms andM-Theory Corrections toD=11Supergravity

We construct a local on-shell invariant in $D=11\mathrm{}$ supergravity from the nonlocal four-point tree scattering amplitude. Its existence, together with earlier arguments, implies nonrenormalizability of the theory at lowest possible, two loop, level. This invariant, whose leading bosonic terms are exhibited, may also express the leading, “zero-slope,” $M$-theory corrections to its $D=11\mathrm{}$ supergravity limit.