The surface of C-60/70(111) thin films on Au(111) has been investigated by scanning tunneling microscopy (STM). Two types of ball-shaped molecules - differing in diameter and corrugation, C-60 and C-70 - build up a hexagonal lattice. The C-70 content in the films, determined by counting the C-70 molecules in the STM images, corresponds well to the C-70 content determined by high pressure liquid chromatography on hexane solutions of the fullerene powders. STM images show lattice defects such as vacancies, interstitials, twin- and stacking boundaries. Dynamic motion of C-70 molecules is observed. Different submonolayer coverages are documented by STM images as a function of film deposition time.