What silent film adapted from the novel "The Clamsman" did Elmer Clifton appear in?
Elmer Clifton:  A collaborator of D.W. Griffith, he appeared in "The Birth of a Nation" (1915) and "Intolerance" (1916) before giving up acting in 1917 to concentrate on work behind the camera, with Griffith and Joseph Henabery as his mentors.
i don't know