Аннотация:A stratigraphical differentiation of Upper Cretaceous deposits from certain sections is presented. It is based on a change detected in the complexes of benthonic foraminifera widely distributed throughout the whole section. The subdivisions are compared with the stratigraphical scheme of Western Kazakhstan. Complexes from non-carbonate argillaceous and siliceous facies, containing "primitive’ forms with a slightly arenaceous casing, are distinctive and difficult to compare. A detailed micropalaeontological division revealed a whole series of discontinuities in the sections and indicated their limits. The division based on foraminifera was compared with data on belemnites and bivalves. Particular attention was directed towards the Santonian-Campanian boundary. -translated by P.Cooke