Pocket forms several decimetres in diameter, 0.5–1.5 m deep and infilled mainly with glaciogenic sands, silts and clays of Saalian age are commonly developed on the top of the karstified chalk massif of the Lublin Upland, eastern Poland. Analysis of lithofacies, particle-size distribution and micromorphology of three pocket infills in the Chełm chalk quarry reveals a prominent clay cortex between the host chalk and the glaciogenic infill and suggests that periglacial processes have played a considerable role in the formation of the pockets and in the redistribution of their primary glaciogenic infill. A conceptual model for epikarst morphogenesis for the chalk karst of Lublin Upland is proposed, involving three stages. Stage I: In the absence of permafrost, precipitation water infiltrates unconsolidated glaciogenic deposits. Stage II: Periglacial transformation with underlying permafrost. Primary cryoturbation structures became protokarst forms, and then epikarst forms. Stage III: Degradation of the permafrost, with increased carbonate dissolution and development of a clay karst cortex. Copyright © 2012 John Wiley & Sons, Ltd.