The Lost Tribe (1949)

THE LOST TRIBE  (1949)  ¢ ¢
    D: William Berke
    Johnny Weissmuller, Myrna Dell, Elena Verdugo,
    Joseph Vitale, Ralph Dunn, Nelson Leigh 
Johnny Weissmuller fights a crocodile and kills a shark, and a lion fights a gorilla and then Johnny fights the lion and stabs it to death. Also, there's a lost city deep in the jungle and some thieves want to steal all the treasure there, but they'll have a tough time doing that as long as Johnny's around, at least that'd be my guess.