The crystallographic and electronic structures of gold ultrathin layers grown on the Si(1 1 1)-(6 x 6)Au surface are investigated with the reflection high energy electron diffraction, scanning tunnelling microscopy, angle-resolved photoemission spectroscopy and density functional theory techniques. It is found that the Au layers consist of crystallites with the (1 1 1) and (1 1 0) orientations in respect to the Si substrate. Both types of crystallites contribute quantum size effect bands to the electronic structure of the film. It is observed in photoemission experiments as two sets of quantum states with significantly different dispersions. Almost linear bands are associated with the (1 1 1) crystallites while the parabolicshaped ones belong to the (1 1 0)-oriented crystallites. The electronic structure is reproduced well by the first principle calculations. (C) 2015 Elsevier B.V. All rights reserved.