Hidden at a well-known viewpoint: try and visit on a clear day if you have the choice. There are two plaques here, one commemorating the Nicholson stamp, another marking the site of the cottage belonging to Tom Shimmin ("Tom the Dipper").
Tom was a 19th century character, described as a "rag-gatherer and poet". Despite being a preacher and teacher he was something of a rogue. See this extract from "Manx Worthies" for more detail.