AbstractAn early and a late calcite cernent are distinguished in limestones of Carboniferous age in N. Wales and Silurian age in Shropshire, England. Solution of aragonite, and preferential pressure solution of carbonate grains in day‐rich beds are considered to be the sources of the early and late cements, respectively. An association between the distribution of ferroan calcite and clay minerals indicates that clays may be an important contributor of iron during the precipitation of the late cernen