Gwennap's Famous Amphitheatre Sept. 14. I preached in the natural amphitheatre at Gwennap; far the finest I know in the kingdom. It is a round, green hollow, gently shelving down, about 50 feet deep; but I suppose it is 200 feet across one way, and nearly 300 the other. I believe there were full 20,000 people; and, the evening being calm, all could hear. April 21.