Monadnock , a geographic term, is an
isolated hill or a lone mountain comprised of bedrock rising above the surrounding area. It is an erosional remmnant of a mountain chain left behind because of its more erosion resistant rock.
... Herjulfsson[?] - Viking discoverer of North America
Thor Heyerdahl, (1914-2002), Norwegian explorer
Henry Hudson, (died 1570), discovered the Hudson River and sailed up ...