The study of calcareous crusts, under the scanning electron microscope (SEM), as features of pedological development on both wet and dry Arctic sites shows that these crusts have a sequence of forms, with varied and complex grain microforms and layered internal structure. The presence of Mg is very variable and is not significantly related to the assumed development sequence. The various carbonate crusts bear witness to the development of pedological features and processes related to the intensive dissolution of carbonates by melt-water, melting ground-ice and summer rainfall, all acidulated by contact with organic matter in the soil. The reprecipitation on the undersides of stones is achieved by intense evaporation of this soil solution and a sequence of precipitated forms is described which is independent of the presence of algae, permafrost-table depth and geomorphic site or age. Grain-size and calcitan thickness are variable at all stages of development.