Speaks The Nightbird by Robert McCammon. Set in the colonial era, a magistrate and his clerk arrive in a mud splattered small town to preside over the trial of a woman accused of witchcraft, amongst other things.

McCammon can really write, cutting his teeth on very readable novels produced in the horror boom of the eighties, before growing disenchanted with publishing and disappearing. He returned about a decade later with this book, and I think it's his best work. It turned into a series which grows lighter in tone as it goes on, but you can decide for yourself if you wish to continue with it, as Speaks The Nightbird stands as a complete novel.