Pure SiC crystals of lamellar and columnar habit were investigated by microscopic and x-ray techniques. All columnar crystals proved to be of one definite polytype without one-dimensional disorder, whereas in most lamellar specimens different polytypes were found in coalescence. Many lamellar crystals showed one-dimensional disorder; in each case it appeared locally and not throughout the specimen. The experimental data suggest that polytypism and one-dimensional disorder are determined by the kinetics of crystal growth.