We found new phenomena that ridge and island structures were naturally formed during the molecular beam epitaxy (MBE) of Zn0.7Cd0.3Se onto GaAs(110) surfaces obtained by cleaving in ultra high vacuum (UHV). In contrast to the mirror-like surface of ZnSe layers, Zn0.7Cd0.3Se epilayers showed two types of structures on the surface, i.e. pyramidal-shaped islands and asymmetric Δ-shaped ridges oriented the [11̄0] direction. The ridges have strong correlation with the underlying dislocations produced by anisotropic in-plane strain relaxation. Local variation of the growth rate due to the strain field caused by the dislocations is suggested as a formation mechanism of such ridge structures.