I believe many of the Lebanon Gerharts could be descendend from Frederick Gerhart of Berks Co., who came from Langenselbold, Hessen (near Frankfurt), Germany. There are a number of Bern township families (Rebers, Kershners, Hetricks et al) who came from this town. It's not my line, so I don't have more information, but I was in Langenselbold doing research on Leinbachs (who also came from there to Berks Co., but not to Bern Twp.), and I noticed the Gerhart entries. I believe there was a genealogy published at some point on this Frederick Gerhart's family.