Hello and Welcome to the Forum, Arcstopper:
A log house of that period is probably sitting on rock piers and used to having plenty of ventilation passing under it. A reliable contractor can raise it, build a new foundation with proper ventilation and use a termite barrier to set the house on. Check his references and ask to see some of his recent jobs, talk to those owners and you will have a good picture of the contractor. It is also a good thing to talk to the local code officials before begining. Let us know how it goes and post picutures; we like 'em.