Two types of spiral growth, single and double spirals, ofC60epitaxial films on a KBr(001) substrate were observed by atomic force microscopy (AFM). These single and double spirals were found on films grown at different rates. All spiral islands show the threefold symmetry of the face-centered-cubic (fcc) structure. In the case of single spirals, many fringes were observed in three equivalent [11¯0] directions on the fcc (111) surface. From the AFM images, we concluded that the growth process of these spirals can be explained by the classical crystal growth theory of Burton, Cabrera, and Frank and that screw dislocations form without any direct influence of the substrate. ©1997 American Institute of Physics.