Business Law!!

Mary, twenty-five years ago, put a fence around a piece of land. At the time, Mary knew that fence not only surrounded her land but possibly also a sizeable piece of Smith's land. Every summer Mary planted a garden on this land surrounded by the fence. Smith recently sold all of his land to Jane. Jane has found out about the fence line and has asked Mary to either move the fence or pay Mary for the land in question. What is the result?