  We calculate the time evolution of the entanglement entropy in a 1+1 CFT with
a holographic dual when there is a localized left-moving packet of energy
density. We find the gravity result agrees with a field theory result derived
from the transformation properties of R\'enyi entropy. We are able to reproduce
behavior which qualitatively agrees with CFT results of entanglement entropy of
a system subjected to a local quench. In doing so we construct a finite
diffeomorphism which tales three-dimensional anti-de Sitter space in the
Poincar\'e patch to a general solution, generalizing the diffeomorphism that
takes the Poincar\'e patch a BTZ black hole. We briefly discuss the calculation
of correlation functions in these backgrounds and give results at large
operator dimension.
