Years ago, I saw an old black and white horror film on television late one night. It had people crossing a "living" swamp which was made of these odd fungus-like creatures that covered the surface of it. The people could walk across the swamp by wearing snow shoes, but I remember one man got pulled in by the creatures. I think there was lots of fog/mist around the swamp as well. Anybody know what the film was?

The Lost Continent (http://www.imdb.com/title/tt0063240/)

Thank you, Quinn! It was indeed The Lost Continent (I just watched it on Google Videos). It was the late 1970s when I saw it on television but I must have watched it on a black & white set and therefore remembered it as a B&W film (it was actually made in 1968 and in colour).

You're welcome.