Patterned ground is present and active on the Avalon Peninsula of Newfoundland, though in the main it is restricted to higher exposed areas of the southern half of that peninsula. The patterned ground forms resemble types previously considered confined, if at low elevations, to more northerly latitudes. Also, a permafrost base had been assumed necessary for construction of certain of the structures, but there presently is no permafrost anywhere on the Avalon Peninsula. Formation of the patterned ground was caused largely by low summer temperatures, general thinness or absence of snow cover in winter, and a strongly maritime climate. Those factors, where combined with sparse vegetation and a hard till underlying the frost-churned soils, can produce most typical patterned ground forms.Presence of such well-developed features on the Avalon Peninsula indicates that fossil frost structures elsewhere should not everywhere be assumed to indicate much more severe climate, perhaps with permafrost, in the past. They may merely indicate an earlier, intensely maritime-type climate with a moderate winter, but a low mean, annual temperature.