We have investigated water adsorption on Pt(111) using chloroform to probe the structure and binding sites available on the ice Surface. A stable adsorption site appears, associated with growth of ice crystallites on the (root 39 x root 39)R16 degrees wetting layer, and disappears slowly as the film grows and loses its registry to the wetting layer. The root 39 multilayer consists of ordered crystalline ice nuclei which aggregate progressively into a Continuous incommensurate ice as the film grows to similar to 40 layers, the entire film and wetting layer restructuring into an oriented bulk ice only for films more than 50 layers thick. (c) 2005 Elsevier B.V. All rights reserved.