Abstract During the colder parts of the Last Gold Stage at some times there were large ice masses, and at others there were periglacial conditions apparently without ice masses. It is a matter of doubt whether ice masses did form early in the Gold Stage, or whether periglacial conditions were dominant for the greater part of the stage, with ice only appearing at a relatively late date; some evidence from Ireland does not appear to tally with that from England. The paper presents a hypothetical frost cycle, and suggests that all the periglacial features created during the Last Cold Stage that have so far been recognized in Ireland could have been formed in two such cycles. The first cycle, which was very severe, perhaps took place at the end of the Early Devensian; the second cycle, which was sharp but short, occurred at the end of the Late Devensian, between 11000 and 10000 B.P ., and corresponds with Pollen Zone III.